Augustine of Hippo
Catena Aurea · Matthäusevangelium 22
But when the Pharisees had heard that he had put the Sadducees to silence, they were gathered together. Then one of them, which was a Lawyer, asked him a question, tempting him, and saying, Master, which is the great commandment in the Law? Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the Law and the Prophets.
(de Doctr. Christ, i. 22.) But if even yourself you ought not to love for your own sake, but because of Him in whom is the rightful end of your love, let not another man be displeased that you love even him for God’s sake. Whoso then rightly loves his neighbour, ought to endeavour with him that he also with his whole heart love God.