Bestow upon me, O Lord my God, understanding to know thee, diligence to seek thee, wisdom to find thee, and a faithfulness that may finally embrace thee.
Thomas AquinasA man should remind himself that an object of faith is not scientifically demonstrable, lest presuming to demonstrate what is of faith, he should produce inconclusive reasons and offer occasion for unbelievers to scoff at a faith based on such ground.
Thomas AquinasSecondly, man sins against nature when he goes against his generic nature, that is to say, his animal nature. Now, it is evident that, in accord with natural order, the union of the sexes among animals is ordered towards conception. From this it follows that every sexual intercourse that cannot lead to conception is opposed to man's animal nature.
Thomas Aquinas