Now I do not know how deep Peter's guilt was here; it was pretty deep, but I cannot say specifically because Luke does not tell us what he was feeling guilty about. Maybe he was feeling guilty for kind of pooh-poohing the idea that Jesus would know where to catch fish. You know, underestimating Jesus. Maybe it was his tone of voice, but maybe it was a lot more than that. Maybe what Jesus had done in this miracle made him think of how totally unworthy he was and he just felt dirty.
He felt sinful. He felt all that guilt come to the surface, and he asked Jesus, his Savior, to leave him because it felt so terrible to have all that guilt come down, pressed down upon him after seeing this miracle. I mean, you would think normally that you would see a great miracle like this, just hundreds of fish in this boat, causing them nearly to sink, and you would be, "Oh yeah, that's great. Look at what happened." Not Peter. It was something that stirred in him this feeling of worthlessness that he did not like.
He liked it so little that he wanted the cause of that, which he determined to be Jesus' righteousness and His holiness, to leave him so he could go back to being normal, have these normal feelings of self-worth. "I'm an okay guy." But standing next to Jesus, he knew he was not an okay guy. He was full of sin, and he felt it to his very bones.