It is often said that we should love one another either because God loved us first or because Jesus has told us we should love one another. But there is a deeper more profound reason for this love we should have towards all humans. We should have this love, care, and compassion because each one of us is made in the image of God. Regardless of how one understands what the image of God is we do know that this is a profound and unique statement only attributed to humanity. The divine image sets us apart from all of creation and it is this reason that we should see the beauty and worth in everyone which should compel us to care and love one another, especially the poor and brokenhearted. Calvin sums this up well in his Institues:
_So that we do not grow weary in well doing — as might otherwise happen at any time — we should also remember what Paul goes on to say: love is patient, and is not easily irritated. The Lord requires us to do good to all he makes no exception, even though most people are unworthy if we judge them on their merits. Scripture, however, forestalls us, warning us to pay no attention to human work in itself but rather to consider the image of God which is in all of us, and which deserves all our respect and affection. Especially should we acknowledge it among God’s servants in the faith, because it is being renewed and restored in them by the Spirit of Christ.
If someone, then, turns up who needs our help, we have no reason to refuse our aid. What if we claim that he is a stranger? We are reminded that the Lord has stamped them with the mark which should be familiar to us: we are thus urged not to despise our own flesh. What if we maintain that the man is worthless and beneath contempt? The Lord replies and he has honored him by causing his own image to shine within him. What if we say we owe him nothing? The Lord tells us that he has put him as a substitute in his own place: we are to think of him as the one for his sake God has distilled his blessing on us. What if we think he is not worth lifting a finger for? We should hazard our lives and goods on account of God’s image which we are meant to see in him. Even supposing the man deserved nothing from us, but instead had grossly abused and injured us, that is no reason to stop loving him, or offering assistance and support. For we argue that he deserves only elbows, God might well ask what ill he himself has done us, he to whom we owe every good thing. For when he commands us to forgive men their sins against us, God ways those sins to his own charge. This is the only way we can attain what is not only difficult for human nature but totally abhorrent to it — loving those who hate us, repaying evil with good, and praying those who slander us. This, I repeat, we can attain if we are careful not to dwell on the evil which men do, but rather look upon the image of God which they bear, and whose worth and dignity can — and should — move us to love them, and to bury their faults which might otherwise repel us._
This is an excerpt from A Guide to Christian Living by John Calvin, which is part of Book 3 of The Institutes of the Christian Religion. The translation is by Robert White, p. 37–40. You can purchase this little book here.