My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous. 1 John 2:1
The word righteous is used in combination with other words in the Bible to express several different names for Jesus-for example, Righteous Branch (Jeremiah 23:5), Righteous Judge (2 Timothy 4:8), and Righteous Servant (Isaiah 53:11). But this is the only place in the King James Version where Jesus is simply called the Righteous. 
Jesus can be called the Righteous or the Righteous One, because He is the only person who has ever lived who achieved perfect righteousness. Although He was capable of doing wrong, because of the human side of His nature, He never gave in to temptation or stumbled into sin.
At the beginning of His ministry, Jesus was tempted by Satan to establish an earthly kingdom and to use His powers for His own self-interest. But Jesus resisted all of these temptations (see Luke 4:1-13). In the garden of Gethsemane on the night before His crucifixion, He admitted that “the flesh is weak” (Matthew 26:41). In an agonizing prayer, He asked God to deliver Him from the suffering of the cross, if possible. But He finally yielded His will to His Father’s purpose and plan (see Matthew 26:37-42).
Because Jesus is the Righteous One, He calls us, His followers, to a life of righteousness. We will never achieve perfection and a sinless existence in this life, but we ought to be growing in that direction. He has promised to guide us along this journey. “The eyes of the Lord are over the righteous,” the apostle Peter declares, “and his ears are open unto their prayers” (1 Peter 3:12).