Now Abraham moved on from there into the region of the Negev and lived between Kadesh and Shur.
For a while he stayed in Gerar, and there Abraham said of his wife Sarah, “She is my sister.” Then Abimelek king of Gerar sent for Sarah and took her. But God came to Abimelek in a dream one night and said to him, “You are as good as dead because of the woman you have taken; she is a married woman.”
Now Abimelek had not gone near her, so he said, “Lord, will you destroy an innocent nation? Did he not say to me, ‘She is my sister,’ and didn’t she also say, ‘He is my brother’?
I have done this with a clear conscience and clean hands.” 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.” Early the next morning Abimelek summoned all his officials, and when he told them all that had happened, they were very much afraid.
Genesis 20 : 1 – 8 (Today’s New International Version)
“Crooked policy will not prosper: it brings ourselves and others into danger.
God gives Abimelech notice of his danger of sin, and his danger of death for his sin. Every wilful sinner is a dead man, but Abimelech pleads ignorance. If our consciences witness, that, however we may have been cheated into a snare, we have not knowingly sinned against God, it will be our rejoicing in the day of evil.
It is matter of comfort to those who are honest, that God knows their honesty, and will acknowledge it.
It is a great mercy to be hindered from committing sin; of this God must have the glory. But if we have ignorantly done wrong, that will not excuse us, if we knowingly persist in it.
He that does wrong, whoever he is, prince or peasant, shall certainly receive for the wrong which he has done, unless he repent, and, if possible, make restitution.”#
# Taken From Matthew Henry’s Concise Commentary.