Men seized of the urge to have a knowledge of God and to be pure in mind devote all their gathered energies to this one task. While they still live in the corruption of the flesh they give themselves to that service in which they will persevere when the corruption has been laid aside. And already they come in sight of what the Lord and Savior held out when He said, 'Blessed are the clean of heart, for they will see God' (Mt. 5:8).
John CassianMore John Cassian quotes
The apostles were very sure that everything of theirs which had to do with salvation was a gift to them from God. 'Increase our faith'. They did not presume that the fullness of faith would come to them merely because they freely opted for it. They believed, rather, that it was a gift of God which would have to be granted to them.
John Cassian
... a Christian is quite certain to fall into the same sins which he condemns in another with merciless and inhuman severity, for 'a stern king will fall into misfortunes,' and 'one who stops his ears so as not to hear the weak, shall himself cry, and there shall be none to hear him' (Prov. 13:17; 21:13).
John Cassian