The problem with the current marketing of Christianity is that it misleads people from Jesus’ original requirement.
Today we invite people to accept or believe in Jesus by inviting Him to live in our hearts as Savior. We describe Christians as believers.
Certainly the gospel of John frequently uses this word for inviting people to Jesus but its meaning then is not the same as our meaning today.
When Jesus walked among us as God He sought to convince people that He was God and the Messiah they were waiting to come. He was Who He said He was and by believing this the people would follow Him as their Messiah/Lord.
We understand belief to be an agreement of or about something but we do not take the word to mean a commitment upon our part as a result of this belief.
Believing in our day is a passive word that requires nothing from us beyond mental agreement. This is best understood by most of in the belief that we could lose a few pounds but we do nothing toward that end.
Demons too believe in Jesus but fail to live a surrendered life to His Lordship of them.
So too the Lord Jesus, God in the flesh, consistently taught that only those who die to self are worthy to be called His people.
Just as Jesus died to Himself, though He was God, He didn’t retain His majesty but humbled Himself taking the form of a man and became a servant sacrificing His life in obedience to the will of God the Father; so too those who are worthy to be called children of God are to be fully surrendered to the will and work of God for His glory to be on earth as it is in heaven.
This means the active engagement in loving people through our sacrifice and service in order to convince others that Jesus is Savior of the world and that He requires people to follow Him.