Ambrosiaster, on Rom 3:4

“But God is true; and every man a liar, as it is written, That thou mayest be justified in thy words, and mayest overcome when thou art judged.”

“Because God is true, he gives what he has promised. To fail is human, for the times and the foolishness of nature make man unstable in that he does not have foreknowledge. But God, for whom there is no future, remains unchanging, as he says: "I the Lord do not change." Therefore Paul says that all men are liars, and this is true. For nature is fallible and is not unreasonably called a liar. It may be a liar intentionally or accidentally, but we must not expect God to be like that, for he is perfect and full of good will and will accomplish what he has promised. He even confirms this by the prophetic oracle: "Thou art justified in thy sentence and blameless in thy judgment."”

Imported from an open dataset — not yet checked against the printed edition.