Luke 18:12

I fast twice, &c.— The sins which the Pharisee mentioned, being such as were severally charged on the publicans, and the duties such as that sort of men were supposed to neglect, it shewed to what an intolerable pitch his vanity was grown, and proved that he possessed none of those virtues, for which he so vainly returned God his solemn thanksgiving. Besides, his fasting twice a week was a duty not prescribed by the law, no more than his paying tythes of all, according to the opinion of most casuists at that time, if, as is probable, he meant tythes of mint, anise, and cummin, a preciseness by which men of his sect made themselves remarkable. See ch. Luke 11:42, Wherefore the language of this part of his prayer was, "I not only far excel other men in point of holiness, but I am more righteous than the law requires." Thus did the proud Pharisee arrogantly insinuate, that he had laid God under an obligation to him. It has been observed by most commentators, that the Jews, especially, the Pharisees, used generally to keep private fasts on Mondays and Thursdays, as the primitive Christians did on Wednesdays and Fridays. But our Lord had formally removed the ostentatious manner of doing it for the direction of Christians. See Matthew 6:1