Genesis 32:24-32

24 Jacob was left alone, and wrestled with a man there until the breaking of the day.  25 When he saw that he didn't prevail against him, he touched the hollow of his thigh, and the hollow of Jacob's thigh was strained, as he wrestled.  26 The man said, "Let me go, for the day breaks."  Jacob said, "I won't let you go, unless you bless me."

27 He said to him, "What is your name?"  He said, "Jacob."  28 He said, "Your name will no longer be called 'Jacob,' but, 'Israel,' for you have fought with God and with men, and have prevailed."

29 Jacob asked him, "Please tell me your name."  He said, "Why is it that you ask what my name is?" He blessed him there.

30 Jacob called the name of the place Peniel: for, he said, "I have seen God face to face, and my life is preserved."  31 The sun rose on him as he passed over Peniel, and he limped because of his thigh.  32 Therefore the children of Israel don't eat the sinew of the hip, which is on the hollow of the thigh, to this day, because he touched the hollow of Jacob's thigh in the sinew of the hip.