Romans 8:3-4 NIV
For what the law was powerless to do because it was weakened by the flesh, God did by sending his own Son in the likeness of sinful flesh to be a sin offering. And so he condemned sin in the flesh, in order that the righteous requirement of the law might be fully met in us, who do not live according to the flesh but according to the Spirit.
Under the old covenant (or Old Testament), God gave His followers laws to obey in order to be right with Him. Because of mankind’s sinful nature, however, no one could keep all of God’s laws perfectly and that is why Jesus died on the cross to pay for our sins.
Now under the new covenant (or New Testament), we are made right with God by putting our faith in Jesus!
While we are not saved by works, we still must walk in the will of God to maintain our relationship with Him. That’s why God gave us His Holy Spirit to empower us and lead us in doing His will.
This doesn’t mean we do not need to obey God’s written Word of Scripture, but it means that the Holy Spirit will show us how to apply it in every unique situation.
For example, the Bible does not tell us exactly how long to pray. It does tell us to pray continually, so as we put in the effort to spend time with God daily, the Spirit of God will convict us if we need to make adjustments (such as pray or read our Bibles more).
Anytime we are following the Holy Spirit, He will lead us into the perfect will of God. He will never lead us to do anything that is displeasing to God. That is why the Bible says in Romans 8 that the requirements of the law are fulfilled in us when we walk after the Spirit (verse 4).
You do not need a long list of do’s and don’ts in order to please God, you just need to follow His Word and the leading of the Holy Spirit.
Galatians 5:16 NIV
So I say, walk by the Spirit, and you will not gratify the desires of the flesh.
Galatians 5:18 NIV
But if you are led by the Spirit, you are not under the law.