John the Apostle
John 8:58BSB·traditional attribution

“Truly, truly, I tell you,” Jesus declared, “before Abraham was born, I am!”

John Calvin Reformed @genevareformer

58. Before Abraham was. As unbelievers judge only from the appearance of the flesh, Christ reminds them that he has something greater and higher than human appearance, which is hidden from the senses of the flesh, and is perceived only by the eyes of faith; and that, in this respect, he might be seen by the holy fathers, before he was manifested in the flesh. But he uses different verbs.

Matthew Henry Presbyterian @wholebiblehenry

In these verses we have, I. The doctrine of the immortality of believers laid down, Joh 8:51. It is ushered in with the usual solemn preface, Verily, verily, I say unto you, which commands both attention and assent, and this is what he says, If a man keep my sayings, he shall never see death. Here we have, 1.

Commenting on John 8:51-59

Albert Barnes Presbyterian @notesbybarnes

Verse 58. Verily, verily. This is an expression used only in John. It is a strong affirmation denoting particularly the great importance of what was about to be affirmed. . Before Abraham was. Before Abraham lived. I am. The expression I am, though in the present tense, is clearly designed to refer to a past time.