John Calvin Commentary Isaiah 8:2

"and I will take unto me faithful witnesses to record, Uriah the priest, and Zechariah the son of Jeberechiah." — Isaiah 8:2 (ASV)

And I took into me witnesses. The noun עדים (gnedim), and the verb אעיד (agnid), which the Prophet employs, are derived from the same root, and the allusion is elegant, as if we were to say, “I have called-to-witness witnesses.” As this was a matter of great importance, he therefore took to himself witnesses, as is usually done on important occasions.

Faithful witnesses. He calls them faithful, that is, true and worthy of credit; yet one of them was an ungodly and worthless apostate, who, wishing to flatter his king, erected an altar resembling the altar at Damascus and openly defended ungodliness and unlawful modes of worship. Some commentators, I am aware, believe that it was a different person; however, a careful examination of the circumstances will convince anyone that this was the same Urijah of whom the sacred history declares that he was slavishly devoted to the ungodliness and lawless desires of the king (2 Kings 16:11).

As for those who think that it was a different person because Isaiah here calls this man faithful, such an argument carries little weight. For the Prophet did not look at the man, but at the office which he held, and which made him a fit person for bearing testimony. Accordingly, he does not mean that he was a good and excellent man, but that his office gave him such influence that nobody could reject him, and that his testimony was, as they say, free from every objection.

Uriah the priest, and Zechariah the son of Jeberechiah. I think that this prophecy was affixed to the gates of the temple, Uriah and Zechariah having been taken to be witnesses. For he does not speak of a vision, but of a command of God, which he actually obeyed, so that these words, like a common proverb, might be repeated by every person.