411. We read:

You are to love the Lord God above all and your neighbour as yourself, Luke 10:27.

Loving the neighbour as oneself means not despising him compared with oneself, dealing justly with him, and not passing wicked judgment upon him. The law of charity promulgated and given by the Lord Himself is this:

Whatever you wish people to do to you, do the same to them; for this is the Law and the Prophets, Matthew 7:12, Luke 6:31-32.

That is how those who are impelled by the love of heaven love the neighbour; but those who are impelled by the love of the world love the neighbour in worldly fashion and for worldly reasons, and those who are impelled by self-love love the neighbour in selfish fashion and for selfish reasons.