Psalms 18:25

“God renders to men according to their deeds in a penal, not vindictive, sense (Lev 26:23-24). merciful--or, "kind" (Psa 4:3).”

“With the merciful - From the particular statement respecting the divine dealings with himself the psalmist now passes to a general statement (suggested by what God had done for him) in regard to the general principles of the divine administration. That general statement is, that God deals with men according to their character; or, that he will adapt his providential dealings to the conduct of men. They will find him to be such toward them as they have shown themselves to be toward him. The word merciful refers to one who is disposed to show kindness or compassion to those who are guilty, or to those who injure or wrong us. Thou wilt show thyself merciful - Thou wilt evince toward him the…”

“Upright - Thou metest to every one the same measure, which he meteth out to others; and therefore thou wilt perform mercy and truth, to those who are merciful and true to others. Psalms 18:26”

“18:25-29 The faithful God remains true to his character. He loves faithfulness, blamelessness, and purity, and he hates the perverse (see 1:6).”

“With the: Psa 41:1-4, Psa 112:4-6; Neh 9:17; Isa 57:1, Isa 57:2, Isa 58:7, Isa 58:8; Mat 18:33-35; Luk 6:35-38 thou wilt: Isa 26:7; Eze 18:25-30; Rom 9:14 Psalms 18:26”