"The short ladder of spiritual progress - which is at the same time both small and great - has five rungs leading to perfection. The first is renunciation, the second submission to a religious way of life, the third obedience to spiritual direction, the fourth humility, and the fifth God-imbued love. Renunciation raises the prisoner from hell and sets him free from enslavement to material things. Submission is the discovery of Christ and the decision to serve Him. As Christ Himself said, 'He who serves Me, follows Me; and where I am he who serves Me will also be' (cf. John 12:26). And where is Christ? In heaven, enthroned at the right hand of the Father. Thus he who serves Christ must be in heaven as well, his foot placed ready to climb up; indeed, before he even begins to ascend by his own efforts he is already raised up and ascending with Christ. Obedience, put into action through the practice of the commandments, builds a ladder out of various virtues and places them in the soul as rungs by which to ascend (cf.Ps. 84:5. LXX). Thence the spiritual aspirant is embraced by humility, the great exalter, and is borne heavenwards and delivered over to love, the queen of the virtues. By love he is led to Christ and brought into His presence. Thus by this short ladder he who is truly obedient swiftly ascends to heaven."
- Saint Gregory of Sinai
Reference: Philokalia: Volume 1