It is the tendency of all rivers to flow to the ocean, but they do not flow there in a straight line; on the contrary, they are continually diversified in accordance with the laws of nature. The rule, applicable in this case to a holy mind, is, that we must leave this tendency under the direction of Providence, and not direct it in our own will. It is true we cannot rightfully be deprived of our own choice; but we are bound to make a right choice, and our choice ought always to be, to let the movements of our hearts be guided by God's choice. The will of the creature is as disastrous here as anywhere else. Let our love, then, flow where Providence indicates that it ought to flow. God, who reveals himself in his providences, and acts through them, and God only, should choose for us.
But supposing that the Providence of God places before us, as the objects of our love, those who are exceedingly depraved and vicious, are we bound to love them in that case? Most certainly we are. They are appropriate objects of [that] love... which loves existences simply because they have an existence....
As the appropriate object of this form of love is existence in distinction from character, it will naturally direct itself, in an especial manner, towards those whom Providence has particularly associated with us, no matter what their characters may be. The mere fact of sentient existence, presented before us as an object of contemplation, will stir up the waters at the heart's fountain; but the relations of Providence will indicate the channels in which they must flow. Our relatives and others, with whom we are particularly associated in providence, may be very wicked. But the fact of their wickedness does not destroy the other and everlasting fact, that they are accountable existences; that they have immortal souls; that they are capable of great happiness or great misery. Fallen, degraded, miserable, they may be; but if we are like God, how can we help loving them? God is a fountain of love, flowing out continually towards all his creatures, sparing not even his own Son to save and bless them, and showing, more than in any other way, his love to those who are his enemies.
— edited from A Treatise on Divine Union (1851) Part 4, Chapter 6.