Many individuals thought the Mosaic Law is good for nothing after they accepted the grace of God through Jesus Christ. Are you aware that the apostle Paul said, “it is those who obey the law who will be declared righteous?”
It is true that a person can be justified by obeying the Law based from the apostle Paul’s writing to the Roman church but with the condition that he will truly keep the whole Law perfectly without offending even one. As expected, no human in the past, present, and even in the days to come can truly follow the Law except Jesus Christ alone who has perfectly fulfilled it. In fact, the more that a person would want to follow the Law because of his self-righteousness, the more guilt and condemnation will be felt because of his inability to follow such divine decree.
Do you think Abraham, who is considered the respected Patriarch of the Judaism followed the Law in its entirety? Surely not!
He lied about his relationship with Sarah.
He committed adultery with Hagar.
The apostle Paul knew their patriarch Abraham cannot be righteous by following the Law because he would surely fail. What Abraham did was only to believe in Yahweh imputing righteousness on him.
Even an individual who thought he has obeyed the Mosaic Law would surely be guilty of pride by elevating himself more than God.
The apostle Paul, who thought he could be righteous by following the commandments finally acknowledged that his own righteousness cannot come from obedience of the Law but through faith in Jesus Christ.
For it is we who are the circumcision, we who worship by the Spirit of God, who glory in Christ Jesus, and who put no confidence in the flesh–though I myself have reasons for such confidence. If anyone else thinks he has reasons to put confidence in the flesh, I have more: circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; in regard to the law, a Pharisee; as for zeal, persecuting the church; as for legalistic righteousness, faultless. But whatever was to my profit I now consider loss for the sake of Christ. What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ and be found in him, not having a righteousness of my own that comes from the law, but that which is through faith in Christ–the righteousness that comes from God and is by faith. Phil. 3:3-9, NIV1984
In the Old Testament, when Abraham believed Yahweh, he was declared righteous. The same also happens in the New Testament that when a person believes in Jesus as his Lord (Yahweh) and Savior (Messiah) then he will be declared righteous in God’s sight. Once that happens then we can now follow God’s righteous commands because it is God who work in us to produce the desires and actions that please him.
References: See Rom. 2:13; Matt. 5:17; Gal. 2:16; 2 Cor. 3:7-9; Jam. 2:10; Gen. 20:2-12; 16:1-46; Rom. 4:3 7; Eph. 2:8-9; Rom. 4:28; Phil. 2:13.