Superstitious If You Don't Quote Heathen Authors

John Calvin commenting on Titus 1:12.

From this passage [Titus 1:12] we may infer that those persons are superstitious, who do not venture to borrow anything from heathen authors. All truth is from God; and consequently, if wicked men have said anything that is true and just, we ought not to reject it; for it has come from God. Besides, all things are of God; and, therefore, why should it not be lawful to dedicate to his glory everything that can properly be employed for such a purpose?