Therefore, even now, when pronouncing psalms, let everyone be confident that God will soon hear those who ask with the psalm word. For if anyone grieves, great consolation will find in them; if he endures temptation and persecution, singing psalms, he will appear skillful and gain the protection of the Lord, Who protected the one who spoke the psalm; with psalms he will put the devil to flight and repel his demons. If anyone has sinned, by reading them he will come to his senses and stop sinning. And whoever has not sinned will rejoice that he competes with those who preceded him and, chanting psalms, wins in battle and will never waver in the truth. His assistant in this is the Divine Scripture itself.
In ancient times, the Israelites, by reading Scripture, cast out demons and exposed the intrigues they perpetrated on people. The words of the saints are terrible for the demons, they cannot bear them, because in the sayings of Scripture - the Lord Himself, whom the demons cried out not tolerating; I beg You, do not torment me (Luke 8:28). So now let the same be read over those who suffer; In this way, help will sooner be provided to the sufferer, and the reader will show his true and firm faith, and therefore God, seeing it, will give perfect healing to those who ask.
Knowing this, the saint said in the one hundred and eighteenth psalm: I will learn from Your justifications; I will not forget Your words (v. 16), and again: Thy vindication was praised to me in the place of my coming (v. 54). For in them the saints acquired salvation, saying: Had it not been for Thy law, my teaching, then I would have perished in my humility (v. 92).
By studying this and reading the psalms in this way, you, guided by the Spirit, will be able to comprehend the meaning of each and will begin to yearn for the same life that the God-bearing holy men who spoke them had.
Saint Athanasius the Great.
Creations. T. IV. M., 1994. P. 4-35