--James 2:12

GK Chesterton on adultery:

"The revolt against vows has been carried in our day even to the extent of a revolt against the typical vow of marriage. It is most amusing to listen to the opponents of marriage on this subject. They appear to imagine that the ideal of constancy was a yoke mysteriously imposed on mankind by the devil, instead of being, as it is, a yoke consistently imposed by all lovers on themselves. They have invented a phrase, a phrase that is a black and white contradiction in two words - ‘free-love' - as if a lover ever had been, or ever could be, free.

"It is the nature of love to bind itself, and the institution of marriage merely paid the average man the compliment of taking him at his word. Modern sages offer to the lover, with an ill-favored grin, the largest liberties and the fullest irresponsibility; but they do not respect him as the old Church respected him; they do not write his oath upon the heavens, as the record of his highest moment. They give him every liberty except the liberty to sell his liberty, which is the only one that he wants."