Theophylact of Ohrid
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.
See how He has enumerated all the powers of the soul; for there is a 1living power in the soul, which He explains, when He says, With all thy soul, and to this belong anger and desire, all of which He will have us give to Divine love. There is also another power, which is called natural, to which belong nutriment and growth, and this also is all to be given to God, for which reason He says, With all thy heart. There is also another power, the rational, which He calls the mind, and that too is to be given whole to God.