Genesis 9:20-23

20Noah began to be a man of the soil, and he planted a vineyard.

21He drank of the wine and became drunk and lay uncovered in his tent.

22And Ham, the father of Canaan, saw the nakedness of his father and told his two brothers outside.

23Then Shem and Japheth took a garment, laid it on both their shoulders, and walked backward and covered the nakedness of their father. Their faces were turned backward, and they did not see their father's nakedness.