Hear me when I call, O God of my righteousness! You have relieved me in my distress; have mercy on me, and hear my prayer.
“God of my righteousness” can also be translated “O my righteous God” (NKJV Study Bible note on Psalm 4:1). God is the source of all righteousness. The Messiah is called “THE LORD OUR RIGHTEOUSNESS” from the Hebrew YHWH Tsidkenu.
In contrast, humanly “all our righteousnesses are like filthy rags” (Isaiah 64:6). “There is none righteous, no not one” (Romans 3:10, quoted from Psalm 14:1-3). It is through Jesus Christ’s sacrifice that we can be made right with God. And it is through using the power of the Holy Spirit that we can begin striving to live a righteous life.
Recognizing God’s righteousness should lead us to seek His help to be righteous like He is.
For more about seeking God’s Kingdom and His righteousness, see “Seek First the Kingdom of God.”