What man, then, of sound mind can possibly suppose that they were ignorant of anything, whom the Lord ordained to be masters (or teachers), keeping them, as He did, inseparable (from Himself) in their attendance, in their discipleship, in their society, to whom, "when they were alone, He used to expound" all things which were obscure, telling them that "to them it was given to know those mysteries," which it was not permitted the people to understand? Was anything withheld from the knowledge of Peter, who is called "the rock on which the church should be built," who also obtained "the keys of the kingdom of heaven," with the power of "loosing and binding in heaven and on earth? " Was anything, again, concealed from John, the Lord's most beloved disciple, who used to lean on His breast to whom alone the Lord pointed Judas out as the traitor, whom He commended to Mary as a son in His own stead? Of what could He have meant those to be ignorant, to whom He even exhibited His own glory with Moses and Elias, and the Father's voice moreover, from heaven? Not as if He thus disapproved of all the rest, but because "by three witnesses must every word be established." After the same fashion, too, (I suppose, ) were they ignorant to whom, after His resurrection also, He vouchsafed, as they were journeying together, "to expound all the Scriptures.
But when "they found not the body (of the Lord Jesus)," "His sepulture was removed from the midst of them," according to the prophecy of Isaiah. "Two angels however, appeared there." For just so many honorary companions were required by the word of God, which usually prescribes "two witnesses." Moreover, the women, returning from the sepulchre, and from this vision of the angels, were foreseen by Isaiah, when he says, "Come, ye women, who return from the vision; " that is, "come," to report the resurrection of the Lord.
Is he then the same God as He who gave Satan power over the person of Job that his "strength might be made perfect in weakness? " How is it that the censurer of the Galatians still retains the very formula of the law: "In the mouth of two or three witnesses shall every word be established? " How again is it that he threatens sinners "that he will not spare" them -he, the preacher of a most gentle god? Yea, he even declares that "the Lord hath given to him the power of using sharpness in their presence!" Deny now, O heretic, (at your cost, ) that your god is an object to be feared, when his apostle was for making himself so formidable!
For if "in the mouth of three witnesses every word shall stand: " -while, through the benediction, we have the same (three) as witnesses of our faith whom we have as sureties of our salvation too-how much more does the number of the divine names suffice for the assurance of our hope likewise! Moreover, after the pledging both of the attestation of faith and the promise of salvation under "three witnesses," there is added, of necessity, mention of the Church; inasmuch as, wherever there are three, (that is, the Father, the Son, and the Holy Spirit, ) there is the Church, which is a body of three.
The wisdom of Paul and his much tender affection, one may observe in many other circumstances, but especially in this, his being so abundant and vehement in his admonitions, but so tardy and procrastinating in his punishments. For he did not chastise them immediately on their sinning, but warned them once and again; and not even so, upon their paying no attention, does he exact punishment, but warns again, saying, "This is the third time I am coming to you;" and "before I come I write again." Then, that his procrastinating may not produce indifference, see how he corrects this result also, by threatening continually and holding the blow suspended over them, and saying, "If I come again I will not spare;" and "lest when I come again I should mourn for many." These things, then, he doeth and speaketh, in this too imitating the Lord of all: because that God also threateneth indeed continually and warneth often, but not often chastiseth and punisheth.
He joins the unwritten to the written, as he has done also in another place, saying, "He that is joined to an harlot is one body; for the twain," saith He, "shall become one flesh." Howbeit, this was spoken of lawful marriage; but he diverted its application unto this thing conveniently, so as to terrify them the more. And so he doth here also, setting his comings and his warnings in the place of witnesses. And what he says is this: "I spoke once and again when I was with you; I speak also now by letter. And if indeed ye attend to me, what I desired is accomplished; but if ye pay no attention, it is necessary henceforth to stop speaking, and to inflict the punishment."
[AD 220] Tertullian on 2 Corinthians 13:1