Jer 23:5-6 KJV Behold, the days come, saith the LORD, that I will raise unto David a righteous Branch, and a King shall reign and prosper, and shall execute judgment and justice in the earth. (6) In his days Judah shall be saved, and Israel shall dwell safely: and this is his name whereby he shall be called, THE LORD OUR RIGHTEOUSNESS.Jesus is the LORD.
The Scriptures call for more than a superficial reading. Jesus spoke in parables to the multitude not to open their eyes but to close them. And the Scriptures throughout are filled with symbolism where one thing represents another. If one is not interested in the deep things of God he will never understand the Scriptures.
The required righteousness of the believer is God's righteousness imputed to the believer. And Jesus is called the righteousness of God because God imputes His righteousness to us through faith in God's promises. The symbolism of the needed righteousness is referred to as clothing. Paul says our own righteousness is as filthy rags.The required righteousness calls for us to "Put on Christ" as a garment. When that happens, God's righteousness is imputed to us by our faith. Just as Abraham's faith was imputed to him for righteousness.
Jesus represents God's righteousness because it is by and through him that the believer is made the righteousness of God. Calling Jesus "YHWH our righteousness" is simply to see that God's righteousness comes through the one whom He appointed and anointed.