John the Apostle
John 21:17ESV·traditional attribution

He said to him the third time, “Simon, son of John, do you love me?” Peter was grieved because he said to him the third time, “Do you love me?” and he said to him, “Lord, you know everything; you know that I love you.” Jesus said to him, “Feed my sheep.

John Calvin Reformed @genevareformer

17. Peter was grieved. Peter undoubtedly did not perceive the object which Christ had in view, in putting the same question so frequently; and therefore he thinks that he is-in-directly accused, as if he had not answered with sincerity. But we have already showed that the repetition was not superfluous.

Matthew Henry Presbyterian @wholebiblehenry

We have here Christ's discourse with Peter after dinner, so much of it as relates to himself, in which, I. He examines his love to him, and gives him a charge concerning his flock, Joh 21:15-17. Observe, 1. When Christ entered into this discourse with Peter.

Commenting on John 21:15-19

John Gill Reformed Baptist @doctorgill

He saith unto him the third time,.... That by these three testimonies, out of his mouth, the thing might be established, and be out of all doubt: Simon, son of Jonas, lovest thou me? is it so indeed that thou lovest me? is thy love really so hearty and sincere as thou savest? may it be depended upon?