Psalm 18, in which David celebrates his deliverance, contains what to many would seem a questionable phrase. In the midst of His praise of God for what He has done, David says in verse 20, “He has rewarded me according to my righteousness.” That would seem to be a very self-righteous statement!
Charles Spurgeon once said that when we cannot claim the kind of righteousness which is found in the Psalms, we can be sure that it refers to JESUS and His perfect righteousness. Such passages are Messianic. All through the Psalms we have foreshadowings of Jesus Christ, the perfect “Son of David” in whom God’s promises for a Savior are fulfilled. Jesus WAS indeed this righteous — and through faith in Him, the New Testament teaches us, we have His perfect righteousness credited to us, too! Romans 3:22 says we are given “even the righteousness of God through faith in Jesus Christ for all those who believe.”
One thing I know for sure: the righteousness David writes of in Psalm 18:20
does not apply to MY own inherent purity! Who among us can say, “The Lord has rewarded me according to my righteousness”? Most of us would admit that would only lead to a death sentence — and worse!
No, the verse MUST refer to Christ’s perfect righteousness; for it cannot apply to ours, which Isaiah rightly says is “filthy rags.” But thank God that it does refer to Jesus Christ, and to the good news of the Gospel that we are freely GIVEN “the righteousness of God through faith in Jesus Christ” when we believe in Him!