Pseudo-Jerome
Catena Aurea · Markusevangelium 12
And one of the scribes came, and having heard them reasoning together, and perceiving that he had answered them well, asked him, Which is the first commandment of all? And Jesus answered him, The first of all the commandments is, Hear, O Israel; The Lord our God is one Lord: And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment. And the second is like, namely this, Thou shalt love thy neighbour as thyself. There is none other commandment greater than these. And the scribe said unto him, Well, Master, thou hast said the truth; for there is one God; and there is none other but he: And to love him with all the heart, and with all the understanding, and with all the soul, and with all the strength, and to love his neighbour as himself, is more than all whole burnt offerings and sacrifices. And when Jesus saw that he answered discreetly, he said unto him, Thou art not far from the kingdom of God. And no man after that durst ask him any question.
This question is only that which is a problem common to all skilled in the law, namely, that the commandments are differently set forth in Exodus, Leviticus, and Deuteronomy. Wherefore He brought forward not one but two commandments, by which, as by two paps rising on the breast of the bride, our infancy is nourished. And therefore there is added, And Jesus answered him, The first of all the commandments is, Hear, O Israel; the Lord thy God is one God. He mentions the first and greatest commandment of all; this is that to which each of us must give the first place in his heart, as the only foundation of piety, that is, the knowledge and confession of the Divine Unity, with the practice of good works, which is perfected in the love of God and our neighbour; wherefore there is added, Thou shalt love the Lord thy God with all thy heart, and with all thy mind, and with all thy soul, and with all thy strength: this is the first commandment.