Judges 16:19-20

19She made him sleep on her knees. And she called a man and had him shave off the seven locks of his head. Then she began to torment him, and his strength left him.

20And she said, "The Philistines are upon you, Samson!" And he awoke from his sleep and said, "I will go out as at other times and shake myself free." But he did not know that the Lord had left him.