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.) Or otherwise; You are commanded to love God with all thy heart, that your whole thoughts—with all thy soul, that your whole life—with all thy mind, that your whole understanding—may be given to Him from whom you have that you give. Thus He has left no part of our life which may justly be unfilled of Him, or give place to the desire after any other final good1; but if aught else present itself for the soul’s love, it should be absorbed into that channel in which the whole current of love runs. For man is then the most perfect when his whole life tends towards the life2 unchangeable, and clings to it with the whole purpose of his soul.