Psalms 115 Summary - The Cambridge Bible for Schools and Colleges
i. In a time of national humiliation Israel supplicates Jehovah to vindicate the honour of His name by raising His people from their degradation. Why should the heathen be allowed to mock, when Israel knows Him to be supreme and omnipotent (Psa 115:1-3)?
ii. How utterly different is He from the speechless, powerless idols which the heathen make and call gods: gods which must drag down their worshippers to their own level of senselessness and impotence (Psa 115:4-8).
iii. Exhortations to trust Jehovah and await His blessing (Psa 115:9-13).
iv. Prayers for blessing and resolves to praise Jehovah (Psa 115:14-18).
This Psalm was probably composed for use in the Temple services after the Return from Babylon, perhaps when the first flush of enthusiasm had died away, and the little community in Jerusalem realised how contemptibly weak it was in the eyes of its neighbours (Ezr 3:3; Ezr 4:1 ff.), perhaps at a later period (Neh 4:1-5); but the sarcastic description of idols in Psa 115:4 ff. points rather to the earlier time, when the memories of Babylonian idolatry were still fresh. Israel’s sense of its own weakness adds strength to its faith in Jehovah, to Whom alone it can look for help and protection.
The precise manner in which the Psalm was intended to be sung cannot be determined with certainty. Psa 115:1-8 may have been sung by the choir of Levites; Psa 115:9 a, 10 a, 11 a by the precentor, answered in Psa 115:9 b, 10 b, 11 b by the choir; and Psa 115:12-18 by the choir. But it is not improbable that Psa 115:12-15 at any rate were distributed between the two halves of the choir. An allusion to such antiphonal singing is found in Ezr 3:11. The priests and Levites “sang one to another (lit. answered) in praising and giving thanks unto Jehovah.” Cp. Neh 12:40.
The opening words of the Psalm, though properly a prayer, have commonly been used as a thanksgiving, as by Henry V after Agincourt  :
 “The king … gathering his armie togither, gaue thanks to almightie God for so happie a victorie; causing his prelats and chapleins to sing this psalme: ‘In exitu Israel de Aegypto’: and commanded euerie man to kneele downe on the ground at this verse: ‘ Non nobis, Domine, non nobis, sed nomini tuo da gloriam.’ ” Holinshed, quoted by Verity, Henry V, p. 227. In the Vulg. Psalms 114, 115 are one Psalm; the first part would have been sung for the dead and dying (see above, p. 680), and the second part as a thanksgiving.
“Do we all holy rites;
Let there be sung ‘Non nobis’ and ‘Te Deum.’ ”
Shakespeare, Henry V., iv. 8. 128.
In some Heb. MSS and in the LXX and versions dependent on or influenced by it (Vulg., Arab., Aeth., Syr., Theodotion, Jerome) this Psalm is united with Psalms 114. But in tone, structure, and style the two Psalms are quite distinct and cannot originally have been one.
Consult other comments:
The Cambridge Bible for Schools and Colleges
The Cambridge Bible for Schools and Colleges is a biblical commentary set published in parts by Cambridge University Press from 1882 onwards. Anglican bishop John Perowne was the general editor. The first section published was written by theologian Thomas Kelly Cheyne and covered the Book of Micah.
Perowne exercised limited editorial control over the writers of individual commentaries: his aim was "to leave each contributor to the unfettered exercise of his own judgment".