Matthew 22:37

Or otherwise; With all thy heart, that is, in all recollection, act, thought; with all thy soul, to be ready, that is, to lay it down for God's religion; with all thy mind, bringing forth nothing but what is of God. And consider whether you cannot thus take the heart of the understanding, by which we contemplate things intellectual, and the mind of that by which we utter thoughts, walking as it were with the mind through each expression, and uttering it.

What then saith Christ? Indicating from what they were led to this; from having no charity, from pining with envy, from being seized by jealousy, He saith, "Thou shalt love the Lord thy God. This is the first and great commandment. And the second is like unto this, Thou shalt love thy neighbor as thyself." But wherefore "like unto this?" Because this makes the way for that, and by it is again established; "For every one that doeth evil hateth the light, neither cometh to the light;" and again, "The fool hath said in his heart, There is no God." And what in consequence of this? "They are corrupt, and become abominable in their ways." And again, "The love of money is the root of all evils; which while some coveted after they have erred from the faith;" and, "He that loveth me, will keep my commandment."

(De Doctr. Christ. i. 30. et 26.) But since the Divine substance is more excellent and higher than our nature, the command to love God is distinct from that to love our neighbour. But if by yourself, you understand your whole self, that is both your soul and your body, and in like manner of your neighbour, there is no sort of things to be loved omitted in these commands. The love of God goes first, and the rule thereof is so set out to us as to make all other loves center in that, so that nothing seems said of loving yourself. But then follows, Thou shall love thy neighbour as thyself, so that love of yourself is not omitted.

(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 good; 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 life unchangeable, and clings to it with the whole purpose of his soul.

But the Lord so answers him, as at once to lay bare the dissimulation of his enquiry, Jesus saith unto him, Thou shalt love the Lord thy God with all thy heart, with all thy soul, and with all thy mind. Thou shalt love, not 'fear,' for to love is more than to fear; to fear belongs to slaves, to love to sons; fear is in compulsion, love in freedom. Whoso serves God in fear escapes punishment, but has not the reward of righteousness because he did well unwillingly through fear. God does not desire to be served servilely by men as a master, but to be loved as a father, for that He has given the spirit of adoption to men. But to love God with the whole heart, is to have the heart inclined to the love of no one thing more than of God. To love God again with the whole soul is to have the mind stayed upon the truth, and to be firm in the faith. For the love of the heart and the love of the soul are different. The first is in a sort carnal, that we should love God even with our flesh, which we cannot do unless we first depart from the love of the things of this world. The love of the heart is felt in the heart, but the love of the soul is not felt, but is perceived because it consists in a judgment of the soul. For he who believes that all good is in God, and that without Him is no good, he loves God with his whole soul. But to love God with the whole mind, is to have all the faculties open and unoccupied for Him. He only loves God with his whole mind, whose intellect ministers to God, whose wisdom is employed about God, whose thoughts travail in the things of God, and whose memory holds the things which are good.