John Calvin Commentary Genesis 32:31

"And the sun rose upon him as he passed over Penuel, and he limped upon his thigh." — Genesis 32:31 (ASV)

And he halted upon his thigh. It is probable, and can even be gathered from the words of Moses, that this limping was without the sensation of pain, so that the miracle might be more evident. For God, in the flesh of His servant, has presented a spectacle to all ages, from which the faithful may perceive that no one is such a powerful combatant as not to carry away some wound after a spiritual conflict. For weakness always clings to everyone, so that no one may be overly pleased with himself.

While Moses relates that the Jews abstained from the shrunken sinew, or that part of the thigh where it was located; this was not done out of superstition. For that age, as we know, was the infancy of the Church; therefore, the Lord kept the faithful who lived then under the instruction of the schoolmaster.

And now, although our condition is more free since the coming of Christ, the memory of this event should be retained among us: that God disciplined His people of old through external ceremonies.