St Isaac the Syrian, Homily 60

It is the spirit of the devil, not the Spirit of God, that dwells in those who pass their life in ease. The Spirit of God is not pleased with bodily comforts, nor does He find a life of ease acceptable, but one of hardships. The devil, on the contrary, is pleased with a life that is filled with comforts, according to the testimony of our Lord. The Holy Spirit withdraws from ease, as the holy Fathers have said, 'The Spirit of God does not dwell in a body that is relaxed by ease.' Rather, the Spirit looks to find where men contrain themselves by afflicting their bodies and readying their souls, and He makes His abode with them, teaching them how to live during the short time of his life. Those who love God live out their lives amid every sort of affliction. For all the righteous have expelled this world from themselves by means of hardships. And to the extent that they draw nigh to God, their hardships increase. - St. Isaac the Syrian, Homily 60