Commentary on Psalms 88

Of Ethan--(See on Psa 88:1, title). This Psalm was composed during some season of great national distress, perhaps Absalom's rebellion. It contrasts the promised prosperity and perpetuity of David's throne (with reference to the great promise of Sa2 7:12-17), with a time when God appeared to have forgotten His covenant. The picture thus drawn may typify the promises and the adversities of Christ's kingdom, and the terms of confiding appeal to God provided appropriate prayers for the divine aid and promised blessing. (Psa. 89:1-52)

mercies--those promised (Isa 55:3; Act 13:34), and--

faithfulness--that is, in fulfilling them.