James 4:17

“Therefore to him that knoweth to do good, etc.] This may regard not only the last particular of referring all things to the will of God, the sovereign disposer of life, and all events, which some might have the knowledge of in theory, though they did not practise according to it; but all the good things the apostle had exhorted to, and the contrary to which he had warned from, in this epistle; and suggests, that a Gnostic, or one that knows the will of God, in the several branches of it, revealed in his word, and doth it not, to him it is sin: it is a greater sin; it is an aggravated one; it is criminal in him that is ignorant of what is good, and does that which is evil, nor shall he escape…”

“The general principle illustrated by the particular example just discussed is here stated: knowledge without practice is imputed to a man as great and presumptuous sin. James reverts to the principle with which he started. Nothing more injures the soul than wasted impressions. Feelings exhaust themselves and evaporate, if not embodied in practice. As we will not act except we feel, so if we will not act out our feelings, we shall soon cease to feel. Next: James Chapter 5”

“Therefore to him that knoweth to do good, and doeth it not, to him it is sin - That is, he is guilty of sin if he does not do it. Cotton Mather adopted it as a principle of action, “that the ability to do good in any case imposes an obligation to do it.” The proposition in the verse before us is of a general character, but probably the apostle meant that it should refer to the point specified in the previous verses - the forming of plans respecting the future. The particular meaning then would be, “that he who knows what sort of views he should take in regard to the future, and how he should form his plans in view of the uncertainty of life, and still does not do it, but goes on recklessly,…”

“Therefore to him that knoweth to do good and doeth it not - That knows what is right, and does not practise it. To him it is sin - This knowledge does not prevent, but increase, his condemnation. Next: James Chapter 5”

“4:17 Remember: This verse is probably a maxim that James expected his readers to recognize. Its source is unknown, but it is consistent with the teaching of Scripture (cp. Deut 24:15; Prov 3:27-28; Matt 25:41-46; Luke 12:47).”

“Luk 12:47, Luk 12:48; Joh 9:41, Joh 13:17, Joh 15:22; Rom 1:20, Rom 1:21, Rom 1:32, Rom 2:17-23, Rom 7:13 Next: James Chapter 5”