On the fourth step of this ladder of love a habitual yet unwearisome suffering is engendered on account of the Beloved. As St. Augustine says: Love makes all burdensome and heavy things nearly nothing [Cf. Sermo 70, De verbis Domini in Evangelium S. Matthei, para. 3] The bride spoke of this step when, desiring to reach the last step, she said to her Spouse: Put me as a seal upon your heart, as a seal upon your arm, for love (the act and work of love) is as strong as death, and emulation and importunity endure as long as hell [Sg. 8:6].
The spirit possesses so much energy on this step that it brings the flesh under control and takes as little account of it as would a tree of one of its leaves. The soul in no way seeks consolation or satisfaction either in God or in anything else; neither does it desire or ask favors of God, for it is clearly aware that it has already received many from him. All its care is directed toward how it might give some pleasure to God and render him some service because of what he deserves and the favors he has bestowed, even though the cost might be high. These persons proclaim in their heart and spirit:
“Ah, my Lord and my God! How many go to you looking for their own consolation and gratification and desiring that you grant them favors and gifts, but those wanting to give you pleasure and something at a cost to themselves, setting aside their own interests, are few. What is lacking is not that you, O my God, desire to grant us favors again, but that we make use of them for your service alone and thus oblige you to grant them to us continually.”
This degree of love is a very elevated step. For as the soul at this stage through so genuine a love pursues God in the spirit of suffering for his sake, His Majesty frequently gives it joy by paying it visits of spiritual delight. For this immense love that Christ, the Word, has cannot long endure the sufferings of his beloved without responding. God affirms this through Jeremiah: I have remembered you, pitying your youth and tenderness when you followed me in the desert [Jer. 2:2]. Spiritually speaking, the desert is an interior detachment from every creature in which the soul neither pauses nor rests in anything. This fourth step so inflames and enkindles individuals with desire for God that it enables them to ascend to the fifth step.
Saint John of the Cross
The Dark Night: Book II, Chap. 19, no. 4