18. Whoever yields too much to one sin, undoubtedly opens a door to many others. Sin never comes alone, but, like a noxious weed, spreads itself on every side, and gains more ground every day. And as the darkness becomes greater accordingly as the sun retires, so as the holy life of Christ departs from us, the darkness and sin increase, till at length the man is swallowed up in eternal darkness. On the contrary, if a man devote himself to the practice of one virtue, he gains thereby an opportunity of practising all the rest in time, and cannot but daily proceed from one to another. This admirable connection is represented by St. Peter as a chain, in which all the rings are linked together, and none is suffered to separate from another. “Add,” he says, “to your faith, virtue; and to virtue, knowledge; and to knowledge, temperance; and to temperance, patience; and to patience, godliness; and to godliness, brotherly kindness; and to brotherly kindness, charity;” superadding one virtue continually to another, and crowning all at last with this promise: “If these things be in you and abound, they make you that ye shall neither be barren nor unfruitful in the knowledge of our Lord Jesus Christ.” 2 Peter 1:5-8. To sum up all in a few words: Whoever is not earnestly bent on the exercise of such heavenly virtues as these, certainly knows not Christ, and is void of all saving knowledge: whereas, if a man by faith grow in virtue, he also grows in Christ himself. On the contrary, the wrathful, the covetous, the proud, the impatient, do not grow in Christ, but in the devil.