1 John 3:17 - Calvin's Commentary on the Bible

17 But whose hath this world’s good, or, If any one has the world’s sustenance. He now speaks of the common duties of love, which flow from that chief foundation, that is, when we are prepared to serve our neighbors even to death. He, at the same time, seems to reason from the greater to the less; for he who refuses to alleviate by his goods the want of his brother, while his life is safe and secure, much less would he expose for him his life to danger. Then he denies that there is love in us, if we withhold help from our neighbors. But he so recommends this external kindness, that at the same time he very fitly expresses the right way of doing good, and what sort of feeling ought to be in us.

Let this, then, be the first proposition, that no one truly loves his brethren, except he really shews this whenever an occasion occurs; the second, that as far as any one has the means, he is bound so far to assist his brethren, for the Lord thus supplies us with the opportunity to exercise love; the third, that the necessity of every one ought to be seen to, for as any one needs food and drink or other things of which we have abundance, so he requires our aid; the fourth, that no act of kindness, except accompanied with sympathy, is pleasing to God. There are many apparently liberal, who yet do not feel for the miseries of their brethren. But the Apostle requires that our bowels should be opened; which is done, when we are endued with such a feeling as to sympathize with others in their evils, no otherwise than as though they were our own.