9. Question. How do some fall after the visitation of grace? Is not Satan shown to be much the weaker? Where it is day, how can there be night?
Answer. It is not that grace is quenched or feeble; but in order that your free-will and your liberty may be tested, which way it inclines, grace makes way for sin ; and then you again draw nigh to the Lord with your will, and entreat that grace may visit you. How is it written, Quench not the Spirit ? (i Thess. v. 19)
The Spirit cannot be quenched, but is always light ; but you, if you are careless and do not with your own will correspond, are yourself quenched and lose the Spirit. In like manner it says, Grieve not the Holy Spirit, whereby ye were sealed unto the day of redemption (Eph 4:30). You see that it lies in your own will and freedom of determination to honour the Holy Spirit and not to grieve Him. I assure you that freedom of choice remains even in perfect Christians, who are subjugated to what is good and intoxicated with it, and the consequence is that, though put to the proof by ten thousand evils, they turn to that which is good.
St. Macarius of Egypt, Homily 27.9, Fifty Spiritual Homilies.