Charles H. Spurgeon on Psalms 119:86

All thy commandments are faithful. He had no fault to find with God's law, even though he had fallen into sad trouble through obedience to it. Whatever the command might cost him it was worth it; he felt that God's way might be rough, but it was right; it might make him enemies, but still it was his best friend. He believed that in the end God's command would turn out to his own profit, and that he should be no loser by obeying it.

They persecute me wrongfully. The fault lay with his persecutors, and neither with his God nor with himself. He had done no injury to anyone, nor acted otherwise than according to truth and justice; therefore he confidently appeals to his God, and cries, "Help thou me." This is a golden prayer, as precious as it is short. The words are few, but the meaning is full. Help was needed that the persecuted one might avoid the snare, might bear up under reproach, and might act so prudently as to baffle his foes. God's help is our hope. Whoever may hurt us, it matters not so long as the Lord helps us; for if indeed the Lord help us, none can really hurt us. Many a time have these words been groaned out by troubled saints, for they are such as suit a thousand conditions of need, pain, distress, weakness, and sin. "Help, Lord, "will be a fitting prayer for youth and age, for labour and suffering, for life and death. No other help is sufficient, but God's help is all sufficient, and we cast ourselves upon it without fear.