"When Noah drank some of it’s wine, he became drunk and lay uncovered inside his tent.

Ham, the father of Canaan, saw his father’s nakedness and told his two brothers outside. But Shem and Japheth took a garment and laid it across their shoulders; then they walked in backwards and covered their father’s nakedness. Their faces were turned the other way so that they would not see their father’s nakedness."

Genesis 9:21-23