Romans 1:16+17,

"For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek. 17 For in it the righteousness of God is revealed from faith to faith; as it is written, The just shall live by faith.”

The gospel of Jesus Christ is that we’re reconciled to God through the Cross, and when reconciled, God endows us with His Spirit so we can fulfill the righteous requirements of the law, by having His Spirit in us.

Romans Chapter 8:1-4,

"There is therefore now no condemnation to those who are in Christ Jesus, who do not walk according to the flesh, but according to the Spirit. 2 For the law of the Spirit of life in Christ Jesus has made me free from the law of sin and death. 3 For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, 4 that the righteous requirement of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit."

What are the righteous requirements of the Law? Matt. 22:37-40,

"You shall love the Lord your God with all your heart, with all your soul, and with all your mind.’ This is the first and great commandment. And the second is like it: ‘You shall love your neighbor as yourself.’ On these two commandments hang all the Law and the Prophets.”