It will be noticed, that we are not commanded to love their enmity,— to love their detractions and ill usage, — but to love that which has enmity; the subject rather than the attribute; namely, their existence, their immortal natures. In the exercise of holy love, we may not only forgive them, but may earnestly seek their happiness; while, at the same time, we condemn their characters. Their characters may change, but not the essence of their being. Their enmity may die, but their nature is eternal.
We repeat, however. that this love cannot be exercised in its full extent, unless the soul has first passed into divine unity and become a partaker of the divine nature. It was this love, resting upon the principle of faith, which constituted Christ the true Son of God. And it is this love, resting upon the same principle of faith, which constitutes the sons of God in all times and all places. "Love your enemies," says the Saviour. And what is the reason which he assigns? "That ye may be the children of your Father which it in heaven, for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust. For if ye love them which love you, what reward have ye? Do not even the publicans the same? And if ye salute your brethren only, what do ye more than others? Do not even the publicans so? Be ye, therefore, perfect, even as your Father, which is in heaven, is perfect."
— A Treatise on Divine Union (1851) Part 4, Chapter 3.