John Calvin Commentary Psalms 119:86

"All thy commandments are faithful: They persecute me wrongfully; help thou me." — Psalms 119:86 (ASV)

All Your commandments are truth. In this verse he again confirms the statement that, in whatever ways he was afflicted, his mind had not been distracted by various devices because, trusting in the word of God, he never doubted His assistance. In the first place, he tells us that the consideration that armed him to repel all assaults was this: that the faithful, under the guidance of God, engage in a prosperous warfare, the salvation they hope for from His word is absolutely certain. For this reason he declares that the commandments of God are true; by this praise he teaches us that those who rely upon the word of God are safe from all danger, and he establishes this truth, that such a support can always sustain our courage.

In the second place, he complains of the treachery of his enemies, as he declared before. Here the word שקר, sheker, is repeated, meaning that they had no regard for equity. From this consideration also he was led to maintain the hope of deliverance, for it is the unique role of God to help the poor and afflicted who are wrongfully oppressed.