A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
psa 85:1On the ground of former mercies, the Psalmist prays for renewed blessings, and, confidently expecting them, rejoices. (Psa 85:1-13)
captivity--not necessarily the Babylonian, but any great evil (Psa 14:7).
psa 85:2(Compare Psa 32:1-5).
psa 85:3To turn from the "fierceness," implies that He was reconcilable, though
psa 85:4having still occasion for the anger which is deprecated.
psa 85:5draw out--or, "prolong" (Psa 36:10).
psa 85:8He is confident God will favor His penitent people (Psa 51:17; Psa 80:18).
saints--as in Psa 4:3, the "godly."
psa 85:9They are here termed "them that fear him"; and grace produces glory (Psa 84:11).
psa 85:10God's promises of "mercy" will be verified by His "truth" (compare Psa 25:10; Psa 40:10); and the "work of righteousness" in His holy government shall be "peace" (Isa 32:17). There is an implied contrast with a dispensation under which God's truth sustains His threatened wrath, and His righteousness inflicts misery on the wicked.
psa 85:11Earth and heaven shall abound with the blessings of this government;
psa 85:12and, under this, the deserted land shall be productive, and men be "set," or guided in God's holy ways. Doubtless, in this description of God's returning favor, the writer had in view that more glorious period, when Christ shall establish His government on God's reconciled justice and abounding mercy.