Verse 17. 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. Cottoa 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, forming his plans boastingly and confident of success, is guilty of sin against God." Still, the proposition will admit of a more general application. It is universally true that if a man knows what is right, and does not do it, he is guilty of sin. If he understands what his duty is; if he has the means of doing good to others; if by his name, his influence, his wealth, he can promote a good cause; if he can, consistently with other duties, relieve the distressed, the poor, the prisoner, the oppressed; if he can send the gospel to other lands, or can wipe away the tear of the mourner; if he has talents by which he can lift a voice that shah be heard in favour of temperance, chastity, liberty, and religion, he is under obligations to do it: and if, by indolence, or avarice, or selfishness, or the dread of the loss of popularity, he does not do it, he is guilty of sin before God. No man can be released from the obligation to do good in this world to the extent of his ability; no one should desire to be. The highest privilege conferred on a mortal, besides that of securing the salvation of his own soul, is that of doing good to others -- of alleviating sorrow, instructing ignorance, raising up the bowed down, comforting those that mourn, delivering the wronged and the oppressed, supplying the wants of the needy, guiding inquirers into the way of truth, and sending liberty, knowledge, and salvation around the world. If a man does not do this when he has the means, he sins against his own soul, against humanity, and against his Maker; if he does it cheerfully and to the extent of his means, it likens him more than anything else to God.

{a} "to him that knoweth to do good" Lu 12:47