These two ways of actually communing with God were beautifully described by the wise Sirach, speaking of wisdom, which is the very grace of God which saves us: For at the first she will walk with him by crooked ways, and bring fear and dread upon him, and torment him with her discipline, until she may trust his soul and try him by her laws. Then will she return the straight way unto him, and comfort him, and shew him her secrets (Sit. 4:17-19).
For at first she will walk with him by crooked ways — that is, austerely, strictly, unmercifully, with a seeming lack of love; and bring fear and dread upon him, the fear of God's abandonment and the ever-imminent threat of attack from vicious enemies. According to St. Diadochus, grace acts like a mother who hides from her children so that from fear they would begin to cry and seek her, especially when they see strange faces before them; and torment him with her discipline — it will keep him a long time in this period of hidden and severe instruction.
According to St. Macarius, grace in many and various ways, as it wills and corresponds to the person's needs, orders everything for him, keeps him in many temptations and mysterious trials of the mind, and so on; until she may trust his soul, and try him by her laws — that is, grace leads him to the point where he can be relied upon completely as one tried and true. St. Macarius says that when after many temptations the will has come to please the Holy Spirit, and over a long period of time has shown itself to be patient and unwavering in this; when the soul does not offend the Spirit in any way, but is cooperative with grace and all the commandments, then will she return the straight way unto him — that is, openly, face-to-face appear to him as if after a separation. Then, according to St. Macarius, "the work of grace is proved to be perfect in him — he acquires full sonship"; or according to St. Diadochus, grace illumines his whole existence with some kind of deep feeling, and he becomes entirely the dwelling-place of the Holy Spirit — the light of God's face (cf. Ps. 4:7). Our Lord and God comes and makes his abode with him (cf. Jn 14:23); and comfort him. And your heart shall rejoice, says the Lord, and your joy no man taketh from you (Jn. 16:22). The Kingdom of God is joy in the Holy Spirit (Rom. 14:17). The light that shines in man, says St. Macarius, so penetrates all the inward parts of a man, that he, immersed in this sweet and pleasant feeling, is totally outside himself because of the super-abundance of love and the hidden mysteries that he himself now sees. St. Diadochus says that the soul then flames and yearns with an indescribable kind of joy and love to leave the body and depart to the Lord, and as if forget this temporary life."
And shew him her secrets — the secrets of divine wisdom, the Trinity worthy of worship, the economy of salvation, the acquisition of salvation, the secret of sin and virtue, Providence for creatures rational and material and, in general, the whole divine order of things, as described in great detail by St. Isaac the Syrian in his epistle to St. Symeon. "When the intellect is renewed and the heart is sanctified... His intellect perceives the spiritual knowledge of created things, and the divine vision of the mysteries of the Holy Trinity together with the mysteries of the worshipful economy on our behalf shines forth in him; then he becomes one through the completeness of the knowledge of the hope of future things... For if the intellect, which beholds hidden spiritual mysteries, is in its natural state of health, it distinctly beholds the glory of Christ. It does not question or receive instruction, but more than in the freedom of the will it delights in the sweetness of the mysteries of the new world..." Such perfect knowledge comes with the receiving of the Spirit, which leads our spirit into that world, or realm of contemplation. The Holy Spirit takes the covering away from the soul, transports his soul to the future age and shows it everything wondrous.
Thus, it is now clear that the grace that comes to the convert through the Sacraments unites with him and gives him at first a taste of all the sweetness of life in God, and then hides its presence from him, leaving him to act on his own in labors, sweat, perplexities and even falls; finally, after this period of trial is over, it abides in him obviously, actively, powerfully, and perceptibly.
Taken from "The Path to Salvation" by St.Theophan the Recluse.