Romans 3:24 (CSB) They (all who believe -vs22) are justified freely by his grace through the redemption that is in Christ Jesus.

This belief is more than the superficial intellectual knowledge of the demons who know who Jesus is (James 2:19). This is a saving knowledge that is deep within your soul and grounded in your actions. Those who have the saving faith in Jesus' work on the cross are given free the grace of God. We do not use this grace to do whatever we please, but to do as God wants us to do.

Galatians 5:13 (CSB)
For you were called to be free, brothers and sisters; only don't use this freedom as an opportunity for the flesh, but serve one another through love.

Luke 17:10 (CSB) "In the same way, when you have done all that you were commanded, you should say, 'We are worthless servants; we've only done our duty.' "