Augustine. Exposition on the Book of Psalms. Schaff, Philip (editor). New York: Christian Literature Publishing Co, 1886. Nicene and Post-Nicene Church Fathers: Series 1: Volume VIII. Re-published 2014, Catholic Way Publishing. Kindle electronic edition, ISBN-13: 978-1-78379-372-3.
“Psalm 119: "Ain"
Psalm 119 prays that the Psalmist should not be given over to his oppressors. Augustine considers it no surprise that the Psalmist would have spoken righteousness, since he had asked God's word to change him (Augustine Psalms, loc. 339720, par. 119). The righteous judgent spoken would be expected to be right. The adversaries, on the other hand, would corrupt judgment. Therefore the Psalmist would pray for endurance (Augustine Psalms, loc. 339729, par. 120). In verse 121 the prayer is to be taken to what is good, a further protection from the evil plans of the adversaries.
Augustine sees a prefiguring of this desire to look at what is righteous in the serpent lifted up by Moses in the wilderness. He sees the fulfillment in Jesus' being lifted on the cross, that all would look to him. In the meantime, verse 123 has the Psalmist looking to God's Word (Augustine Psalms, loc. 339733, par. 122). This is a means by which God deals with his servants in mercy (v. 124).
Augustine takes verse 125 to speak of the necessity of continuing in God's Word, gaining understanding. This is the essence of growing in godliness (Augustine Psalms, loc. 339742, par. 124). The growth we attain with God's guiding hand is exemplified by Christ's coming in the fullness of time. He establishes his rule, which Augustine sees as a good and gracious thing (Augustine Psalms, loc. 339746, par. 125). This is God's affirmation of the integrity of his kingdom.
In light of God's grace, then, the Psalmist loves God's commandments (Augustine Psalms, loc. 339750, par. 126). They are worth more to him than precious gems. All of the commandments (v. 128) guide the Psalmist where he needs to go.