2:10-19 Many spoiled this good work, by going about it with unholy hearts and hands, and were likely to gain no advantage by it. The sum of these two rules of the law is, that sin is more easily learned from others than holiness. The impurity of their hearts and lives shall make the work of their hands, and all their offerings, unclean before God. The case is the same with us. When employed in any good work, we should watch over ourselves, lest we render it unclean by our corruptions. When we begin to make conscience of duty to God, we may expect his blessing; and whoso is wise will understand the loving-kindness of the Lord. God will curse the blessings of the wicked, and make bitter the prosperity of the careless; but he will sweeten the cup of affliction to those who diligently serve him.
13. On the other hand, a legally "unclean" person imparts his uncleanness to any thing, whereas a legally holy thing cannot confer its sanctity on an "unclean" person (Nu 19:11, 13, 22). Legal sanctity is not so readily communicated as legal impurity. So the paths to sin are manifold: the paths to holiness one, and that one of difficult access [Grotius]. One drop of filth will defile a vase of water: many drops of water will not purity a vase of filth [Moore].