2 Timothy 1:5

In thy grandmother Lois, &c.— This is one internal mark, among a multitude, of the genuineness of this epistle: for we find, Acts 16:1 that Timothy was of Jewish descent by his mother's side, but not by his father's. This, and many other such minute particulars, could not all of them have been exactly hit upon, if the writers of the New Testament had not been in those very circumstances, in which we suppose them to have been, when they wrote the several books ascribed to them. Perhaps the apostle, in reckoning up the pious ancestors of the pious evangelist, might have some reference to the second commandment: for, in a sense consistent with moral liberty, God will have mercy upon thousands of generations of them that love him, and keep his commandments.