Ellicott's Commentary On The Whole Bible
Psalms 111 - Introduction
CXI.
Psalms 111, 112 should be read closely together, the one being a pendant of the other. They are both acrostics of at once the simplest and most perfect construction, each clause (not, as usual, each verse of two or more clauses) exhibiting the alphabetical arrangement. There are therefore exactly twenty-two clauses, nearly of three words each. In order to limit the number of verses to ten — considered a perfect number — the last two verses in each psalm are arranged as triplets.
The close relation of the two psalms is also exhibited in their subject. The first exhibits Jehovah in covenant with man; the second, man in covenant with Jehovah. The one sings the Divine praise in view of the kindness God has shown to Israel; in the second, the feeling of the just man — i.e., the Israelite faithful to the covenant, is the subject. In both we discover the strength of these religious convictions, which, in spite of the contradictions experienced in actual life, persist in maintaining the grand principle of Divine justice, and declaring that the cause of virtue will triumph, and success and wealth never fail the faithful.
The close relation of the two psalms is marked by the echo in the second, of phrases applied in the first to Jehovah. (Comp. e.g., Psalms 111:3, with Psalms 112:3; Psalms 112:9; Psalms 111:4, with Psalms 112:4; Psalms 112:6.)