Commentaria in Deuteronomium
From what has been said it is plain that this precept can be fulfilled literally in this life. For we can love God with all our possibility, that is, as far as is possible according to the state and infirmity of this life; and so it must be, because otherwise it would be commanded us in vain in this life, and so God would command impossibilities, which no one can perform. Finally, that king Josias and the like fulfilled this precept is plain from 4 Kings xxiii, 25. See Bellarmine, book II On Monks, chapter xii.
Wherefore it is not necessary with Jansenius to take refuge in hyperbole, and to expound this precept hyperbolically; as if to say: Thou shalt love God with thy whole heart, that is, so that thy chief thought and love be occupied about God; as we commonly say: This man is wholly in his studies, the rest he does in passing. For this hyperbole makes an improper sense, and lowers the force and energy of this first and greatest commandment.
By this precept, then, there is required of man the whole and supreme love of God, not extensively or intensively, but only comparatively, finally and appreciatively. First, comparatively, that is, that thou give so wholly thy heart and affection to God that thou give no part of it to a demon or to sin. So Vasquez, I-II, Question CCIX, article 3; second, finally, that in general thou have God as the end of all thy actions, and prefer him, as the supreme good and last end, to all things, so that thou wouldst rather lose all things, nay thy life, than God and the grace of God; third, appreciatively, that thou apply the whole heart, that is, thy will, to obey his law in all things, so that thou conform thyself in all things to his holy will; and therefore love him with full love, not only of concupiscence, but also of friendship. Hence what is here said, “With thy whole heart,” is elsewhere said, “With a perfect heart,” or: “His heart was perfect with God,” and: “He walked in all the commandments of the Lord.” For in this precept of love all the particular precepts of God are contained virtually, as conclusions are contained in their principles; both because the love of God includes obedience to God; and because, as God is the idea and most perfect mirror, in which things appear more perfectly, and are seen by the Blessed, than in themselves, so also he is the whole good, which is most lovable, and in him is the order of things lovable; he being loved, therefore, we shall love all things which are lovable, says Abulensis.
And this is the cause why in the charity and love of God all the perfection of this life, Christian as well as Mosaic, consists, as the Fathers and Doctors teach. For the rest, such as “fasts, watchings, meditation of the Scriptures, nakedness and privation of all possessions, are not perfection, but instruments of perfection,” says Abbot Moses in Cassian, Conference I, chapter vii.
You will ask secondly, why God is to be loved with the whole heart? I answer: The cause a priori is first, because God is the creator, giver and preserver of the heart itself, and of all natural and supernatural goods which are in the heart and in the whole man; it is fitting, therefore, that all these return to him, and as it were flow back by love. For the love of God is the highest worship and honour of God. Hence St. Augustine, Sentences, sentence 344: “That,” he says, “is worshipped by man which he loves. Hence because God is found greater and better than all things, he is to be loved more than all, that he may be worshipped.” Hence St. Bernard, epistle 333, to one asking “what God requires of us,” answered: “Nothing can more worthily perfect our heart than that it restore itself to him by whom it was made, and this the Lord asks of us, saying: Son, give me thy heart. Then indeed is the heart of men given to God, when every thought ends in him, turns and bends about him, and wishes to possess nothing at all beside him, and so, the mind bound to him, loves him that without him all love is bitter; nor would I say that to give the heart to the Lord is anything else than to make it captive to all his service, and so to subject it wholly to his will that it wish nothing but what it knows he wills. Therefore the heart given to the Lord will adore him in all things and for all things, and give thanks, even though many things seem grievous to our senses, etc. He who has given his heart to God will sing melodiously, and say with the Prophet David: My heart is ready, O God, my heart is ready; I will sing and give praise in my glory, etc. Therefore all who have delivered their heart to God sing psalms in tribulations, in distresses, in straits, in hunger and thirst, in nakedness and dejection, in curses, in reproaches and derisions, in scourges, and even when death is threatened, in their hearts they rejoice more. To give the heart to God is estrangement from the world and from oneself, and to be made in God by virtue and to rest in him by the invisible and remote peace of the mind,” etc.
Secondly, because God created the heart, or mind, to his image and likeness: hence he gave it a certain infinite capacity, which can be filled and satisfied by no creature, but by God alone: “The heart is small,” says Hugh, On the Soul book III, “and desires great things; it could scarcely suffice for the refreshment of one kite, and the whole world does not suffice for it.” And this is what St. Augustine says: “Thou hast made us for thyself, O Lord, and our heart is restless till it rest in thee.” God is therefore the centre of our heart and love; hence Abbot Anthony said: “I love God, I do not fear.”
Thirdly, because God, as he is the beginning, so is the end of man and of all creatures; all ought therefore to follow and love him, as such, with the whole heart and affection. Wherefore weighty authors relate that St. Augustine, in his delights and colloquies of love with God, was wont to address God thus: “Lord, my soul exceedingly rejoices in thee, while it thinks that thou art our God. Wherefore if, by an impossibility, it could be that Augustine were God, and thou wert Augustine, I would altogether wish that thou shouldst be God, not Augustine.” Which saying is surely to be rightly understood; I shall explain it (God willing) in my next work on the Prophets, Ezechiel viii, 3 and 5.
Fourthly, because God is the supreme, immense and uncreated good, which is the fountain of all good, and which contains in itself all goods, both created and possible, in the most eminent and perfect degree; therefore he is supremely lovable; therefore to be loved with the whole heart: for other goods compared with God are vain and nothing, smoke and shadow, and therefore are not to be loved for themselves, but only for God: “All abundance which my God is not, is poverty,” says St. Augustine. Rightly, therefore, did Blessed Jacopone, drunk with the love of God, weep continually, and being asked the cause, gave this: “Because Love (God) is not loved.” Rightly did Blessed Magdalen, as a hart wounded by the arrows of the love of Christ, say: “I sought him whom my soul loveth through the streets and the broad ways; I found him, I held him, and I will not let him go.” Rightly for thirty years in a rough cave she fed herself most sweetly on his love alone, so that Petrarch rightly sings of her:
For hunger, cold, the hard rocks, the bed, love made sweet,
For the sweetness of divine love, when it has occupied the heart of anyone, makes all sweetness of the world and flesh grow bitter, and bitterness grow sweet. Blessed Gregory Nazianzen, who had experienced this, writes thus to Nemesius:
For if Christ from his citadel on high should strike thy breast, and fix an arrow in the midst of thy heart; looking keenly at each love apart, thou wilt see well how much sweeter the Lord’s goad is.
Who would not melt with love if he beheld God made man for him, Jesus a little child, Jesus labouring, Jesus crucified? Rightly St. Augustine, On Holy Virginity, chapter lv: “Let him,” he says, “be wholly fixed in your heart who for you was fixed on the cross.” And the Spouse: “Stay me up with flowers, compass me about with apples, because I languish with love.”
St. Catherine of Siena, wounded by the wound of the love of Christ her spouse, earnestly asked of him that he would tear out her heart and her own will by the roots, that she might pass wholly into his love. She seemed to herself to see Christ taking her heart from her side, and after some days bringing another shining heart and saying: “Behold, my daughter, thou hast my heart for thine.” Thenceforth, wholly changed, she burned wonderfully with the love of Christ.
King Josaphat, as Damascene testifies in his Life, chapter xxxvii, burning with this love, left his kingdom, exchanged purple for sackcloth, withdrew from the court into the desert, trampled pleasures, riches and glory as dung, and with a joyful mind gave himself to all the hard and bitter exercises of monastic life, crying out that saying of the Psalmist: “My soul hath stuck close to thee,” and: “As the hart panteth after the fountains of water, so my soul panteth after thee, O God.” So, exulting in poverty, he ran through the desert seeking his master Barlaam, to whom afterwards to the end of his life he adhered joyfully and constantly in that austerity.