...we should realize that there are three sources for our thoughts - God, the devil, and ourselves.
John CassianWe must, with God's help, eradicate the deadly poison of the demon of anger from the depths of our souls. So long as he dwells in our hearts and blinds the eyes of the heart with his somber disorders, we can neither discriminate what is for our good, nor achieve spiritual knowledge, nor fulfill our good intentions, nor participate in true life; and our intellect will remain impervious to the contemplation of the true, divine light; for it is written, 'Man's anger does not bring about the righteousness of God' (Jms. 1:20).
John CassianIt is not our free will but 'it is the Lord who sets the captive free' (Ps. 145:7). It is not our own virtue but 'it is the Lord who lifts up those who were laid low' (Ps. 145:8). It is not application to reading but 'it is the Lord who gives light to the blind' (Ps. 145:8). It is not our cautiousness but 'it is the Lord who protects the stranger' (Ps. 145:9). It is not our endurance but 'it is the Lord who raises or gives support to the fallen' (Ps. 144:14).
John CassianAll of our holy fathers knew this and all with one accord teach that perfection in holiness can be achieved only through humility.
John Cassian