Matthew
Matthew 16:17ESV·traditional attribution

And Jesus answered him, “Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven.

John Calvin Reformed @genevareformer

17. Blessed art thou, Simon Bar-Jona. As this is life eternal, to know the only true God, and him whom he hath sent, Jesus Christ, (John 17:3,) Christ justly pronounces him to be blessed who has honestly made such a confession. This was not spoken in a peculiar manner to Peter alone, but our Lord’s purpose was, to show in what the only happiness of the whole world consists.

Matthew Henry Presbyterian @wholebiblehenry

We have here a private conference which Christ had with his disciples concerning himself. It was in the coasts of Cesarea Philippi, the utmost borders of the land of Canaan northward; there in that remote corner, perhaps, there was less flocking after him than in other places, which gave him leisure for this private conversation with his disciples.

Commenting on Matthew 16:13-20

John Gill Reformed Baptist @doctorgill

And I say also unto thee,.... Either besides what he had already said concerning his happiness; or, as the father had revealed something great and valuable, so likewise would he; or inasmuch as he had freely said and declared who, and what he was, in like manner he also would say what Peter was, thou art Peter: intimating, that he was rightly called Peter, or...