Most of us will have had the experience of some long-standing, but distant, friend turning up unannounced on our door-step. If we've dropped out of touch – and we know it was our fault – we may be embarrassed – or glad they've come to find us.

But what if we opened the door and found the Lord on our door-step?! Wasn't it rather like that with Abram, when the Lord appeared to him?

Thirteen years have passed since the birth of Ishmael – 14 or more years since God had solemnly established his covenant with Abram. Fourteen years seemingly, of silence on God's part. Was Abram conscious that there was an estrangement between them? – or did he suppose that all was well?

These were the years of Ishmael's childhood. Not easy ones for Abram, Sarai – or for Hagar. Had Abram any idea how God thought about it? How many of us have been in such a state of uncertainty? Or are in it now? Feeling that faith and worship have become dry and routine. Unhappy that others seem to be enjoying a walk with God of greater blessing and joy than one has oneself. Not sure whether you are going in the right direction.

1. God brings RENEWAL to his friendship with Abram.

And then God comes and speaks a clear word, I am God Almighty. Walk before me and be blameless. God Almighty – El Shaddai – the God who is all-sufficient. Abram, you didn't need to listen to Sarai's advice, or act like your worldly contemporaries. Your responsibility was to trust me. But I have come to confirm the covenant I made with you.

What joy! What relief! No doubt all Abram's doubts – any conviction that all was not well – have been brought to the surface – but God has forgiven him! Abram falls on his face in adoration and thankfulness. He's not been said to have done this before – so there is no doubt that their relationship is restored – their friendship renewed.

God's pleasure is signalled by his giving Abram a new name – Abraham. A new name – because not only is the friendship renewed – but God is giving him a new dignity, a new character. He is to be the father of many nations.

God wants to give each of us a new dignity, a new character. Indeed, if we have asked Jesus into our life as Lord and Saviour, he has already done so – for he has made us his son or daughter by adoption and new birth. There can be no greater honour than that.

Nevertheless, are you wishing that God would come again into your life, in power and assurance? That is his sovereign prerogative. But we all have this word spoken to us today – just as it was spoken to Abraham – Walk before me! What does that mean? It was the word spoken of the servant of a king, who stood and served in the king's presence. It means, Live in my presence!

Of course, those words are a command – but God's commands are also words of power. What he asks of us he will enable us to perform, if we ask him. But these words don't just mean – be conscious of being seen by God, exposed to his sight in everything we do. Of course, we know that must be true – God does see us, even our inmost thoughts. But so often we want to forget that. Like Adam and Eve, we want to hide, because we are ashamed.

No, what he wants us to do – is to live openly before him, seeking always to obey and to please him. Trustful of his love and care – of his willingness to keep and bless us. Then our life will be a joyful walk in which everything is shared and enjoyed with him. We are wholly exposed – but also wholly loved and befriended.

Walk before me – and be blameless! Abraham was not blameless – and neither are we. But God is calling us not to be content with any superficial faith, any shallow obedience. As Dr A.J.Gordon once said, I would rather aim at perfection and fall short of it, than aim at imperfection and come up to it! If our attitude will be that of the king's servant – we shall want to give him our utmost commitment. And in response he gives us his utmost attention and support – I will be your God. (17:7,8; Rev 21:3,7) How much more we should know that – who know God's love in Jesus!

2. God gives Abraham a REMINDER.

Now this commitment on God's part – this covenant – comes from God's initiative. It's a blessing God gives. Abraham's obedience hasn't earned it – that's quite clear. But his obedience, and ours, should flow from gratitude. But God knows that Abraham needs a reminder. So the Lord now insists on the sign of circumcision.

Circumcision was a rite practised from remote antiquity by many tribes in the Eastern Mediterranean – but not in Mesopotamia – and not, evidently, in Abraham's family. For those people who practised it then, it was a rite of puberty and a sign of tribal kinship.

But for Abraham's family – from the outset – it was going to be a religious rite and not a social one. (17:11) It would unite not just the blood-relatives of Abraham – but all men who shared a common covenant-relationship with God. (17:12) [Women were included in the covenant – in those days by association with the men.] Even a blood-relative – if he failed to keep this requirement (17:14) – would exclude himself from the covenant community and God's blessing. So it was to be a sign of obedience to God – and in the future it was to be given in infancy.

Why did God insist upon this? Because – despite their solemn agreement – Abraham had gone his own way. He must have an unmistakeable and ineradicable reminder of the covenant. So it had to be something physical. Because the covenant had to do with Abraham's family and its increase – and because Abraham had expressed his independence in a sexual way – a sign in the flesh of his sexual organ was the obvious choice. Circumcision was to be a reminder of God's friendship and forgiveness. Every day – in bed with Sarah in the tent – or relieving himself outside the tent – he could remind himself that God had forgiven and forgotten. El Shaddai is my friend. With him I have everything. I cannot go my own way.

Abraham obeyed that very day. But, of course, no outward sign could guarantee his trust – still less that of his descendants. As Paul comments, True circumcision is not something external and physical... real circumcision is a matter of the heart, spiritual and not literal. (Rom 2:28,29 RSV) Certainly there is no merit in any religious rite, in itself alone. In Christ Jesus neither circumcision nor uncircumcision has any value. The only thing that counts is faith expressing itself through love... Neither circumcision nor uncircumcision means anything; what counts is a new creation. (Gal 5:6; 6:15) God looks for a transformed heart – not some mutilation of the body – or even a body washed in water.

Nevertheless, it is God who provides us with these outward signs. We are embodied spirits – and we should be glad he strengthens our trust in him – and feeds our love for him, as when we come to his table and receive the bread and wine as reminders of Jesus' dying for us. So our taking them becomes an outward expression of our trusting Christ in our hearts, to receive all the benefits of his death.

In the same way, Abraham's obedience strengthened his faith and sealed his commitment to God. If we have not been baptized – or if we've never publicly ratified our commitment to Christ – then we fall short of God's command to us – as Abraham would have done, if he had refused to be circumcised – even though he'd entered the covenant with God 14 years before.

Being circumcised marked the end of Abraham's isolation from God – and the beginning of a new and closer walk with God. But there was still much to be put right before further blessing could be received.

3. God's REFUSAL.

All Abraham's hopes and ambitions for 13 years had been centred on Ishmael. But he had no assurance that God looked upon Ishmael in the same way. And neither do we, when we have engineered our own schemes and then asked God to bless them.

We have an uncomfortable feeling that we are away from God's will for our lives. We may pretend – to others, at least – that we have been led by God. Or we may make the best of it, because we can't go back. We plod on, carrying all the burden of it ourselves. So it was that Abraham hoped Ishmael was God's choice, too.

But God does his work in his own way. Man's self-effort is contaminated with pride, self-sufficiency and self-centredness. God cannot incorporate that – least of all in a model for future generations. You see, each of us becomes a child of God by a miracle of new birth – the work of God's Holy Spirit – and not by the efforts of some preacher or the best of human endeavours.

God had waited until Abraham and Sarah were too old to have children naturally. As a result – it would always be known that Isaac was a miracle-baby. The very existence of Israel depended alone on what God had done – and not on what man had contrived.

But that hurts our pride! So, when God says explicitly that Abraham's heir will be a son born to Sarah – Abraham's reaction is to laugh in shocked surprise – and then to say, May Ishmael live in your presence! (17:18 NJB)

Although he does promise to bless Ishmael, God says quite plainly – No – to Ishmael's being Abraham's heir. Even though he knows Abraham will be hurt. When we receive God's refusal over some cherished hope or ambition of ours – he says no to save us from worse sorrow. He may do it to humble our pride and independence – and lead us back into paths of blessing. We have to let go our Ishmaels – our own way of doing things – so that we may experience the work of God's Spirit in our lives. Abraham couldn't believe in God's gift of Isaac, because his heart was set on Ishmael. One or the other had to be given up.

David Prior, in his book, Living by Faith, tells of a young divorcee, converted to a genuine, vibrant faith in Christ. In her loneliness she was soon paid much loving attention by a man who was not a Christian. Her new-found faith told her that this wasn't a relationship with a future – but she kept it going – still hoping – but getting more confused and unhappy. When she eventually came honestly to God, she knew he was saying, No – and after a painful tussle, she accepted his word to her, and entered into peace.

It isn't easy to receive God's No about anything we cherish – however it appears to others. I knew for a long time that my hobby of stamp-collecting was getting in the way of my walk with God. But I used all kinds of excuse to put off God's requirement. But when I did, I was free to hear God's voice calling me forward – and to receive his enabling.

Of course, God will not force us to go on in the Christian life. We may be content to stay where we are, content with the blessing we have already received. But so often, in doing so, we refuse God's best for us – and our lives become like Ishmael's – blessed, but with no outcome of eternal significance. Abraham's obedience shows that he did indeed want God's best. Do we?

4. God brings REALISATION of his sovereign love.

God also had to deal with Sarah. In chapter 18 we have the lovely story of the three strangers who come to Abraham's encampment in the noon-tide heat. They receive the ready, respectful and generous hospitality of their host. It was a question of entertaining angels without knowing it! (Heb 13:2) Eventually, the one who was the Lord himself, reveals his knowledge of Sarah's name, and of the promise God had made to them.

Had Abraham shared that promise about Isaac with Sarah? We are not told, but I suspect not, because of her attitude to Hagar and Ishmael. But, when she overhears the stranger say she is to have a son – her laughter is one of incredulity – the laughter of the sceptic. But it is a silent laugh within the heart, which only God hears. So when the stranger reveals his knowledge of it – Sarah is afraid. Now she suspects who he really is – she lies to cover it up.

But God wants us to face the truth about ourselves. As her husband left with the strangers – what a tumult her thoughts must have been in. Her unbelief known to God – yet here he was, bringing her the blessing and future she'd longed and hoped for all her life. It was so hard to believe! But the words were still ringing in her ears, Is anything too hard for the LORD? Too hard? the word is Too wonderful! – the same word Isaiah uses when he speaks of the Messiah as the Wonderful Counsellor (Isa 9:6).

I think, as she went back to wash the dishes – she realised nothing would ever be the same again. She realised that the Sovereign God had touched her life – and she couldn't avoid him – even in her thoughts. Even the name of her son – He laughs – would remind her of that. And God had told her that she would have a boy – even before he was conceived – and that that son would have many descendants. Surely God was going to smile on Isaac!

For our God delights in turning the laughter of incredulity into the laughter of sheer joy. There was nothing left for Sarah to do – except trust, give thanks, and commit herself to the future God had planned for her. He was in charge. Like Mary, in response to the same words, Nothing is impossible with God! – all she – or we – ought to say is, I am the Lord's servant – may it be to me as you have said. (Luke 1:37,38)

Living by faith means accepting God's right to rule over our lives – and accepting gladly the responsibility that comes with that – not going our way – but going God's way. If we do that, we will be walking before him – living in his presence – and our friendship will have been renewed.

                                                                                             Amen.