The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, [1916], at sacred-texts.com
Now you may mark this: that some men receive the gifts of God as hirelings, but others as faithful servants of God; and these differ one from another in all inward works, that is, in love and intention, in feeling and in every exercise of the inward life.
Now understand this well: all those who love themselves so inordinately that they will not serve God, save for their own profit and because of their own reward, these separate themselves from God, and dwell in bondage and in their own selfhood; for they seek, and aim at, their own, in all that they do. And therefore, with all their prayers and with all their good works, they seek after temporal things, or may be strive after eternal things for their own benefit and for their own profit. These men are bent upon themselves in an inordinate way; and that is why they ever abide alone with themselves, for they lack the true love which would unite them with God and with all His beloved. And although these men seem to keep within the law and the commandments of God and of Holy Church, they do not keep within the law of love; for all that they do, they do, not out of love, but from sheer necessity, lest they shall be damned. And, because they are inwardly unfaithful, they dare not trust in God; but their whole inward life is doubt and fear, travail and misery. For they see on the right hand eternal life, and this they are afraid of losing; and they see on the left hand the eternal pains of hell, and these they are afraid of gaining. But all their prayers, all their labour and all the good works, whatsoever they do, to cast out this fear, help them not; for the more inordinately they love themselves, the more they fear hell. And from this you may learn that their fear of hell springs from self-love, which seeks its own.
Now the Prophet, and also the Preacher, say: The fear of the Lord is the beginning of wisdom; but by this is meant that fear which is exercised upon the right side, where one considers the loss of eternal blessedness, for this fear arises from the natural tendency which every man has in himself to be blessed, that is, to see God. And therefore, even though a man may be faithless to God, yet whenever he truly observes himself from within, he feels himself to be leaning out from himself towards that blessedness which is God. And this blessedness he fears to lose; for he loves himself better than God, and he loves blessedness wholly for his own sake. And therefore he dare not trust in God. And yet this is that Fear of the Lord which is the beginning of wisdom and is a law to the unfaithful servants of God: for it compels a man to leave sin, and to strive after virtue, and to do good deeds, and these things prepare a man from without to receive the grace of God and become a faithful servant.
But from that very hour in which, with God's help, he can overcome his selfhood—that is to say when he is so detached from himself that he is able to leave in the keeping of God everything of which he has need—behold, through doing this he is so well pleasing to God that God bestows upon him His grace. And, through grace, he feels true love: and love casts out doubt and fear, and fills the man with hope and trust, and thus he becomes a faithful servant, and means and loves God in all that he does. Behold, this is the difference between the faithful servant and the hireling.