John Calvin on John 13:37

37. Why cannot I follow thee now? By these words Peter declares that he was dissatisfied with Christ’s answer. He is aware that he has been warned of his own weakness, from which he concludes that it is his own fault that hinders him from following Christ immediately; but he is not at all convinced of it, for mankind are naturally puffed up with confidence in their own value. This expression of Peter shows the opinion which we entertain from our very birth, which is, that we attribute more to our own strength than we ought to do. The consequence is, that they who can do nothing venture to attempt every thing, without imploring the assistance of God.