Albert Barnes' Bible Commentary
Psalms 117 - Introduction
The occasion and the author of this psalm are alike unknown. DeWette regards it as a temple-psalm, and agrees with Rosenmuller in the supposition that it was sung either at the beginning or the end of the service in the temple. Knapp supposes that it was used as an intermediate service, sung during the progress of the general service to vary the devotion, and to awaken a new interest in the service, either sung by a choir or by the whole people.
In many manuscripts of Kennicott and De Rossi, and in several editions of the Scriptures, this psalm is united with the following. The psalm has no independent character or meaning of its own, and seems to have been designed, like the “Doxologies” in our Books of Psalms and Hymns, to be attached to other psalms as occasion might require. There is no psalm designed for public worship to which it might not thus properly be attached.