Origen

If every commandment is fulfilled in this one word, Thou shalt love thy neighbour as thyself, and if he is perfect who has fulfilled every command, how is it that the Lord said to the young man, If thou wilt be perfect, when he had declared, All these have I kept from my youth up. Perhaps that he says, Thou shalt love thy neighbour as thyself, was not said by the Lord, but added by some one, for neither Mark nor Luke have given it in this place. Or otherwise; It is written in the Gospela according to the Hebrews, that, when the Lord said, Go, and sell all that thou hast, the rich man began to scratch his head, being displeased with the saying. Then the Lord said unto him, How sayest thou, I have kept the Law, and the Prophets, since it is written in the Law, Thou shalt love thy neighbour as thyself? For how many of thy brethren sons of Abraham, clothed in filth, perish for hunger? Thy house is full of many good things, and nothing goes thereout to them. The Lord then, desiring to convict this rich man, says to him, If thou will be perfect, go and sell all that thou hast, and give to the poor; for so it will be seen if thou dost indeed love thy neighbour as thyself. But if he is perfect who has all the virtues, how does he become perfect who sells all that he has and gives to the poor? For suppose one to have done this, will he thereby become forthwith free from anger, desire, having every virtue, and abandoning all vice? Perhaps wisdom may suggest, that he that has given his goods to the poor, is aided by their prayers, receiving of their spiritual abundance to his want, and is made in this way perfect, though he may have some human passions. Or thus; He that thus exchanged his riches for poverty, in order that he might become perfect, shall have assistance to become wise in Christ, just, chaste also, and devoid of all passion; but not so as that in the moment when he gave up all his goods, he should forthwith become perfect; but only that from that day forward the contemplation of God will begin to bring him to all virtues. Or again, it will pass into a moral exposition, and say, that the possessions of a man are the acts of his mind. Christ then bids a man to sell all his evil possessions, and as it were to give them over to the virtues which should work the same, which were poor in all that is good. For as the peace of the Apostles returns to them again, (Mat. 10:13.) unless there be a son of peace, so all sins return upon their actors, when one will no longer indulge his evil propensities; and thus there can be no doubt that he will straightway become perfect who in this sense sells all his possessions. It is manifest that he that does these things, has treasure in heaven, and is himself become of heaven; and he will have in heaven treasure of God’s glory, and riches in all God’s wisdom. Such an one will be able to follow Christ, for he has no evil possession to draw him off from so following