The mind that is never off the search of itself and the quest of the Lord avails to gain possession of its own soul – the soul that was in the perdition of the passions – by always bringing itself into captivity to the Lord with main force and earnestness, and by cleaving to Him only, as it is said, “bringing into captivity every thought to the obedience of Christ” (2 Cor. 10:5); that by means of such striving and longing and seeking the mind may attain to become with the Lord one Spirit (1 Cor. 6:17) of the gift and grace of Christ.
[…] Lovely it is, when the soul, devoting herself wholly to the Lord, and cleaving to Him only, and dwelling mindfully in His commandments, and worthily honouring the Spirit of Christ which has come upon her and overshadowed her, is permitted to be one Spirit and one composition with Him, as the apostle says, He that is joined unto the Lord is one Spirit (1 Cor. 6:17).
But if a man gives himself away to cares, or glory, or power, or human honours, and seeks after these things, and his soul is mixed up and enters into composition with earthly considerations, or is bound and held by anything belonging to this age, and if such a soul longs to transfer itself and escape and get away from the darkness of passions, in which it is held by the evil powers, it cannot do so, because it loves and does the will of darkness, and does not perfectly hate the practices of wickedness.
Let us therefore prepare ourselves to travel to the Lord with an undivided will and purpose, and to become followers of Christ, to accomplish whatever He wills, and to think upon His commandments to do them (Psalm 102/103:18). Let us sever ourselves altogether from the love of the world, and attach our souls to Him only, and keep in mind Him only as our business and care and quest.
If we have to be somewhat busied also in body, with the business laid upon us, and with obedience for God’s sake, let not the mind be parted from its love and quest and longing after the Lord; so that striving in such a mind, and journeying along the way of righteousness with an upright intention, and always taking heed to ourselves, we may obtain the promise of His Spirit, and may through grace be delivered from the perdition of the darkness of the passions, by which the soul is exercised, that we may be made meet for the eternal kingdom, and permitted to enjoy all eternity with Christ, glorifying the Father, the Son, and the Holy Spirit forever.
Macarius the Egyptian (c. 300-391) [attributed]: Spiritual Homily 9, 11-13, trans. by A.J. Mason DD.