Genesis 20:6 & 7
Then God said to him in the dream, 'Yes, I know you did this with a clear conscience, and so I have kept you from sinning against me. That is why I did not let you touch her. Now return the man's wife, for he is a prophet, and he will pray for you and you will live. But if you do not return her, you may be sure that you and all who belong to you will die.'
We see that it was God who had kept the king from touching Sarah and we are reminded that we must rely on Him to overcome whatever we face. If we will listen and follow the leading of the Spirit, we can be sure that He will keep us from sin. We also see that God's favor was still upon Abraham and it would be displayed for the king by God answering Abraham's prayer on his behalf. He was to go and have Abraham pray on his behalf to save himself and his family. James said that "the prayer of a righteous man is powerful and effective" (see James 5:16) and so we know that the same power is at work today. Unlike Abimelek, we do not have to go to someone else to have them pray for our needs. In Christ, we are made righteous and can ask for what we need on our own. That brings up questions about prayer lists, prayer chains, and getting together for prayer services: Are they more harm than good? The answer is maybe. If believers are thinking that they must be a part of that in order to have their prayers heard and answered, it is really forgetting the fact that Jesus died in order to give us personal access. If Christians are getting together to pray for others, it can be useful to build others up in the faith. When they see the prayers answered, it can build them up in their faith but we must be careful to say that it only takes one Christian to pray for God to hear and act on their behalf. Anything else is close to Nicolaitism which Jesus denounced in His letters to the churches (see Revelation 2). The sad fact is that many prayer chains and services degrade into gossip festivals which do not glorify God. For more on this, check out our modern parable titled Simon's Tears.