"Christ, and Christ alone, is the source of righteousness, that is, the righteousness that we need and becomes ours by God's act of justification. God has worked out a righteousness in Christ for penitent, believing sinners, and this righteousness is now in that exalted Christ at the right hand of God in Heaven. To grant us and bestow on us this righteousness of God (by imputation), God is pleased to use faith. Faith is the bond of union with Christ through which the sinner receives righteousness."
- Rev. David Engelsma, "Gospel Truth of Justification," pp. 141-2
In this paragraph, Engelsma paraphrases what Paul tells us about the failure of the Jews: "Israel, who pursued a law that would lead to righteousness, did not succeed in reaching that law. Why? Because they did not pursue it by faith, but as if it were based on works" (Romans 9:31-32). Where was true righteousness to be found? "Now the righteousness of God has been manifested apart from the law, although the Law and the Prophets bear witness to it- the righteousness of God through faith in Jesus Christ for all who believe" (Romans 3:21-22).
Jesus addressed this problem with the Pharisees: "Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs, which outwardly appear beautiful but within are full of dead people's bones and all uncleanness. So you, also,m outwardly appear righteous to others, but, within, you are full of hypocrisy and lawlessness" (Matthew 23:27-28).
For the unbelieving Jews, righteousness was a matter of checking off a list of do's and don't's. This is the way of pseudo-Christian cults even to this day: Catholics, Mormons, Jehovah's Witnesses, Seventh-Day Adventists. But it is not the way of Biblical Christianity, which is a righteousness by faith alone, the perfect righteousness of Christ, applied only by the gift of faith. "For our sake, He [the Father] made Him [Jesus, the Son] to be sin who knew no sin, so that, in Him, we might become the righteousness of God" (II Corinthians 5:21).