A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown [1882] at sacred-texts.com
The forms of expression and figure here used are frequent (compare Psa 9:12, Psa 9:18; Psa 10:11-12).
How long . . . for ever--Shall it be for ever?
The counsels or devices of his heart afford no relief.
lighten mine eyes--dim with weakness, denoting approaching death (compare Sa1 14:27-29; Psa 6:7; Psa 38:10).
rejoice--literally, "shout as in triumph."
I am moved--cast down from a firm position (Psa 10:6).
Trust is followed by rejoicing in the deliverance which God effects, and, instead of his enemy, he can lift the song of triumph.