What does it mean to rest in the finished work of Jesus Christ?
The entire Bible was about the law and prophets.
The law commanded them to be perfect and righteous (Deuteronomy 6)
The people of the Bible had to follow Jesus in fulfilling the law by faith. They had to receive the power of the Holy Spirit to do this by faith in Jesus (Matthew 5, Luke 11, Romans 8, Romans 13, James 2, John 13)
They could not rest but they had to endure by faith to attain righteousness (Revelation 12-14)
But nobody could do it because they failed in the great tribulation of AD70 (Matthew 24, 2nd Thessalonians 2)
The Biblical faith ended in AD70.
The giving of the Holy Spirit ended in AD70.
Therefore the law ended in AD70 and Jesus did not judge the world (Hebrews 8:13)
Jesus died on the cross to remove the law.
There is no law today. There are no sinners and there is no judgment (Romans 4:15)
Jesus has made the world righteous.
There is no future judgment day!
There is no hell or devil or 2nd coming.
We don’t believe to become righteous.
We accept that Jesus has already made us righteous without works or faith.
We stop trusting in our works and see that Jesus has done everything!
That is how we REST in the finished work.