Psalm 18:20 New English Translation

²⁰The Lord repaid^[a] me for my godly deeds;^[b]
he rewarded^[c] my blameless behavior.^[d]

Psalm 18:20 tn In this poetic narrative context the prefixed verbal form is best understood as a preterite indicating past tense, not imperfect.
Psalm 18:20 tn Heb “according to my righteousness.” As vv. 22-24 make clear, the psalmist refers here to his unwavering obedience to God’s commands. In these verses the psalmist explains that the Lord was pleased with him and willing to deliver him because he had been loyal to God and obedient to his commandments. Ancient Near Eastern literature contains numerous parallels. A superior (a god or king) would typically reward a subject (a king or the servant of a king, respectively) for loyalty and obedience. See R. B. Chisholm, “An Exegetical and Theological Study of Psalm 18/2 Samuel 22” (Th.D. diss., Dallas Theological Seminary, 1983), 211-13.
Psalm 18:20 tn The unreduced Hiphil prefixed verbal form appears to be an imperfect, in which case the psalmist would be generalizing. However, both the preceding and following contexts (see especially v. 24) suggest he is narrating his experience. Despite its unreduced form, the verb is better taken as a preterite. For other examples of unreduced Hiphil preterites, see Pss 55:14a; 68:9a, 10b; 80:8a; 89:43a; 107:38b; 116:6b.
Psalm 18:20 tn Heb “according to the purity of my hands he repaid to me.” “Hands” suggest activity and behavior.

New English Translation (NET)