God made him who had no sin to be sin for us, so that in him we might become the righteousness of God.
(2. Corinthians 5:21)
One of the big difference between the Old and the New covenant is how righteousness is obtained.
Under the old covenant it was something you worked for by living right and offering sacrifices according to the law. The problem was that nobody could was able to do this as perfectly as a perfect God required.
As it is written: “There is no one righteous, not even one...
When people sinned, they could offer sacrifices for sin, but the sin within was not removed, so it was just a matter of time before they again needed to offer new sacrifices.
Another problem was that since sin within was not removed, man was not really righteous in the first place. This meant that even though God was gracious and forgave the wrong they had done, they could never really become righteous because they had already fallen short.
The new covenant
But things changed under the new covenant, but contrary to what many believe it was not God who changed.
Many have an image of God in the Old Testament as grumpy but now under the new covenant He has become happy. This is not the case, because according to James 1:17 God never changes. God has always been good,
“The Lord, the Lord, the compassionate and gracious God, slow to anger, abounding in love and faithfulness, maintaining love to thousands, and forgiving wickedness, rebellion and sin…
But now apart from the law the righteousness of God has been made known, to which the Law and the Prophets testify. This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile,
Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him.
If you love me, you will keep my commandments… “If anyone loves me, he will keep my word… Whoever does not love me does not keep my words
John 14:15, 23-24
They only way we can obtain righteousness, is if God chooses to give it to us; and this is what He does in Christ Jesus.
To be justified mean that you declared not guilty in the charges someone has accused you of. The devil is accusing mankind before, but when we get justified, we are declared not guilty in these charges.
all have sinned and fall short of the glory of God, and all are justified freely by his grace through the redemption that came by Christ Jesus.
And you, who were dead in your trespasses and the uncircumcision of your flesh, God made alive together with him, having forgiven us all our trespasses, by canceling the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross.
But the grace of God is not that He now chooses to take lightly on our sin. The grace of God is that He now solves our problem with sin. He does this through the new birth. The old guilty me was nailed to the cross with Christ and buried in the baptism. In Christ I am a totally new creation, not guilty of what the old me have done.
Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come.
2. Corinthians 5:17
He has no need, like those high priests, to offer sacrifices daily, first for his own sins and then for those of the people, since he did this once for all when he offered up himself.
...he entered once for all into the holy places, not by means of the blood of goats and calves but by means of his own blood, thus securing an eternal redemption.
And by that will we have been sanctified through the offering of the body of Jesus Christ once for all… But when Christ had offered for all time a single sacrifice for sins, he sat down at the right hand of God… Therefore, brothers, since we have confidence to enter the holy places by the blood of Jesus
Hebrews 10:10, 12, 19
You are because of the redemptive work of Jesus Christ both righteous and justified and can now come boldly before God.