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 115:1, Augustine claims that praise is due the Lord primarily due to his mercy, by which he provides for the needs of his people (Augustine Psalms, loc. 338635, par. 1). In verse two we see the joining of mercy and truth. God's judgment is in truth but he shows mercy in judgment so as to let the nations know he is the merciful God (Augustine Psalms, loc. 338644, par. 2). This, to Augustine, explains verse three and the use of "heaven above." This is not merely in heaven but at an exalted place in heaven (Augustine Psalms, loc. 338644, par. 3).
Verse four contrasts God with the idols made by humans. Augustine observes the difference between a god made of materials and a divine presence in the Holy Spirit, who cannot be made (Augustine Psalms, loc. 338656, par. 4). In verses 5-7 the weaknesses of the idols are described. This leads Augustine to observe that the people who make the idols are infinitely greater than the idols themselves (Augustine Psalms, loc. 338664, par. 5). Even the wild animals are more expressive than the idols, sometimes even expressing their superiority by building nests in idols.
Augustine observes that some would seem superior in what they worship, but that Paul condemns all of it in Romans 1 when he rejects worship of the creation (Augustine Psalms, loc. 338677, par. 6). There is a possible objection in the creation of objects used in worship, for instance, the vessels for the Sacrament. Yet these are used in worship but not to be worshiped (Augustine Psalms, loc. 338689, par. 7). Verses 8-9, then, go on to describe the difference. Those who trust idols are blind. Those who hope in the Lord see clearly (Augustine Psalms, loc. 338694, par. 8).
In the end, all our hope is centered on the mercy of God (vv. 10-13). For this reason, we find a benediction in verse 14. God raises up children to draw all nations together in one, in Christ (Augustine Psalms, loc. 338706, par. 10). The Psalm then continues speaking of the blessed nature of God's people. Again, Augustine finds this to come through God's merciful provision (Augustine Psalms, loc. 338719, par. 12).