Rashi on Genesis 12:19/רש"י על בראשית י״ב:י״ט

1קח ולך TAKE HER AND GO AWAY — Not as Abimelech who said to him (Genesis 20:15) “Behold, my land is before thee; dwell wherever it seemeth proper to thee”: but he (Pharaoh) said to him, “Go and do not stay here,” for the Egyptians are greatly addicted to lewd-living, as it is said. (Ezekiel 23:20). “And whose issue is like the issue of horses” (Midrash Tanchuma, Lech Lecha 5). (The passage deals with the immoral practices of the Egyptians).