Genesis 12:12
Therefore it shall come to pass, when the Egyptians shall see thee, that they shall say, This is his wife: and they will kill me, but they will save thee alive. Therefore it shall come to pass, when the Egyptians shall see thee, that they shall say, This is his wife: and they will kill me, but they will save thee alive.
The verse belongs to Abraham's trial when severe famine in the land caused him to go down into Egypt. It expresses his fear that when the Egyptians saw Sarai as his wife they would kill him but save her alive. The episode records a failing in his conduct. God gave him favor with the Egyptians, so that when he left Egypt he had more than when he went in.
Even there his life served as a light to the people, revealing God's character through integrity and benevolence. This account of the sins, frailties, struggles and falls of even favored believers is truthfully preserved as a warning and lesson for later generations. Readers can learn from it, see their need of God's grace, and be encouraged to keep going, rise again and overcome.