6 From these enemies how can any man say that he is safe? For this I had begun to speak of, but I thought it necessary to treat of these enemies at some little length. But now that we know our enemies, let us see to our defence against them. “In praising I will call upon the Lord, so shall I be safe from mine enemies.” You see what you have to do. “In praising call;” that is, “in praising the Lord, call.” For you will not be safe from your enemies, if you praise yourself.
“In praising call upon the Lord, and you shall be safe from your enemies.” For what does the Lord Himself say? “The sacrifice of praise shall glorify Me, and there is the way, in which I will show him My salvation.” Where is the way? In the sacrifice of praise. Let not your foot then wander out of this way. Keep in the way; depart not from it; from the praise of the Lord depart not a foot, nay, not a nail's breadth. For if you will deviate from this way, and praise yourself instead of the Lord, you will not be safe from your enemies; for it is said of them, “They have laid stumbling-blocks for me by the way.” Therefore in whatever measure you think that you have good of your own self, you have deviated from the praise of God.
Why do you marvel then, if your enemy seduces you, when you are your own seducer? Hear the Apostle, “For if a man think himself to be something when he is nothing, he seduces himself.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)