We have a tendency to fall back into sin, doing the very thing we know is wrong. When we seem to “get away” with a sin, the temptation grows to try it again.
Genesis 20 records that for a second time Abraham lied about Sarah’s status—calling her his sister, rather than his wife. It’s possible that they used this technique regularly, “everywhere we go” (v. 13). Having no reason to doubt Abraham’s word, Abimelech, the king of Gerar, sent for Sarah, and rather than admitting his lie, Abraham let her go. Whether Abraham recognized it or not, the stakes were higher this time. When they were in Egypt, Sarah was barren (see Genesis 12). But as they moved to Gerar, Sarah was fertile. The long-awaited promised son would be born within the year. If Sarah spent even one night with Abimelech, Isaac’s paternity could have been called into question. The entire covenant was on the line. God did not allow Abraham’s folly to muddle matters (v. 6).
His sovereignty is on full display throughout this narrative. God appeared in a dream to Abimelech at just the right time. He opened Abimelech’s heart to receive the message with humility and fear. God, thus, kept Sarah from spending the night with Abimelech and protected the clear paternity of Isaac. He closed and opened the womb of all the women in Abimelech’s household (vv. 17–18). He even blessed Abraham abundantly through Abimelech in spite of his ruse. And He worked through Abraham to make Himself known to the people of Gerar. Grace upon grace! What a wonderful reassurance that God will keep His covenant. He will carry out His plan. He is able—in spite of us.