What does Genesis 12:16 mean?
First, Abram and Sarai lied to protect Abram from any Egyptians who would kill him to take Sarai as their own wife. Perhaps he hoped that as her brother he would be able to refuse any marriage proposals. The lie came in the form of a half-truth: that Sarai was Abram's (half) sister. The intent, however, was to make others think she was not Abram's wife, and this made even a truthful statement into a lie.This scheme backfired. Instead of approaching Abram to request Sarai's hand in marriage, or leaving her alone entirely, Pharaoh apparently just took her as his wife, and made some kind of payment to Abram after the fact. The bride price or honor payment included livestock, work animals, and human servants. Abram's scheme had increased his wealth, but lost him his wife.
Abram's fears of losing his wife and his life were justified, but he failed to take those fears to the Lord who had promised to protect and provide for him. He failed to trust the Lord to provide a solution he could not see. This is a classic example of good intentions being perverted by foolish actions (Job 5:13). Abram's own godless actions actually instigated what he feared most!