Your testimonies that you have commanded are righteous and very faithful.
All Commentaries on Psalms 119:138 Go To Psalms 119
Augustine of Hippo
AD 430
136. Thus, then, as if giving a reason why he had cause to weep much, and to mourn deeply for his sin, he saith, "Righteous art Thou, O Lord, and true is Thy judgment" (ver. 137). "Thou hast commanded Thy testimonies, righteousness, and Thy truth exceedingly" (ver. 138). This righteousness of God and righteous judgment and truth, is to be feared by every sinner: for thereby all who are condemned are condemned of God; nor is there one who can righteously complain against the righteous God of his own damnation. Therefore the tears of the penitent are needful; since if his impenitent heart were condemned, he would be most justly condemned. He indeed calleth the testimonies of God righteousness: for He proveth himself righteous by giving righteous commandments.And this is truth also, that God may become known by such testimonies.