2 Think you that my testimony of myself is better than that of God? When the Lord Himself teaches, and says that testimony is not true, if any one himself appears as a witness concerning himself, for the reason that every one would assuredly favour himself. Nor would any one put forward mischievous and adverse things against himself, but there may be a simple confidence of truth if, in what was announced of us, another is the announcer and witness. “If,” He says, “I bear witness of myself, my testimony is not true; but there is another who bears witness of me.” but if the Lord Himself, who will by and by judge all things, was unwilling to be believed on His own testimony, but preferred to be approved by the judgment and testimony of God the Father, how much more does it be-hove His servants to observe this, who are not only approved by, but even glory in the judgment and testimony of God!
But with you the fabrication of hostile and malignant men has prevailed against the divine decree, and against our conscience resting upon the strength of its faith, as if among lapsed and profane persons placed outside the Church, from whose breasts the Holy Spirit has departed, there could be anything else than a depraved mind and a deceitful tongue, and venomous hatred, and sacrilegious lies, which whosoever believes, must of necessity be found with them when the day of judgment shall come.
Source: The Epistles of Cyprian (New Advent)