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.
Commenting on Psalm 118:1, Augustine notes that our primary confession of God is that He is good (Augustine Psalms, loc. 338837, par. 1). Jesus himself, when addressed as 'Good Master" received it and affirmed that this was a confession of his deity. Verses 2-4 emphasize that not only the priests, but all who confess the Lord speak of His mercy (Augustine Psalms, loc. 338845, par. 2).
God's goodness is particularly seen in verse six, when we recognize that the Lord helps us in all our trouble (Augustine Psalms, loc. 338854, par. 3). Augustine sees the argument to continue along the same lines when, in verse eight, we even put our trust in the Lord rather than in our friends. Whatever our toil or struggles, God in Christ keeps us (Augustine Psalms, loc. 338867, par. 5). Verse 12, comparing persecutors to a hive of bees, then, to Augustine describes Jesus, surrounded by enemies, overcoming them, bringing the hive of sweet honey to his people (Augustine Psalms, loc. 338876, par. 6). In contrast to Jesus, verse 13 speaks of God's people being driven as a heap of sand. Augustine takes this to refer to Christians who are gathered together into one body (Augustine Psalms, loc. 338884, par. 7). They are gathered by the Lord, rather than being scattered by their enemies (v. 14). Thus God is their salvation (Augustine Psalms, loc. 338888, par. 8). The result, in verse 15, is joy in Christ.
The joy of the Christian, according to verse 16, is that God has exalted His people (Augustine Psalms, loc. 338897, par. 10). They have obtained eternal life even in the face of death (v. 17). This victory, says Augustine, is not because of the power of the Christian, but because of the power of Christ, who is even the one who permits opposition and suffering, only to keep his people through it all (Augustine Psalms, loc. 338906, par. 12).
In vrse 19, the righteous ask God to open the gates of righteousness. Within there are no wicked men. In this way, Augustine says, the confession is one of praise to God (v. 21), made in his safety (Augustine Psalms, loc. 338919, par. 15). Here the Lord is the cornerstone (v. 22) who has reconciled his people to God.
The day the Lord has made becomes a day of rejoicing (v. 24). Augustine then sees verse 25 as a valid plea. God who has made a day of salvation is the blessed one, coming in his own name. All others who come in their own names are therefore cursed (Augustine Psalms, loc. 338932, par. 20). The true danger we face is receiving those who come in other names. God is the true Lord (v. 27).
Augustine again affirms that we rightly respond by singing God's praise (Augustine Psalms, loc. 338949, par. 22). He is the merciful and gracious one (v. 28).