The gospels contain several accounts of people leaving something behind for the sake of wholeheartedly following Jesus.
* Simon & Andrew "left their nets" (Matt. 4:18-20)
* James & John "left their boat and their father" (Matt. 4:21-22)
* The woman at the well "left her water jar" (John 4:28-30, 39-42)
* Matthew left his career (Matt 9:9)
* The grateful leper left the 9 others (Luke 17:11-19)
Basically, in order to fully follow Christ, we may have to leave behind possessions, earthly treasures, family, occupation, or the group (clique). Of course this is not always easy. For example, Matt. 19:16-22 gives account of a law-abiding rich young man who came to Jesus to inquire about following Him. When Jesus told the man to first sell what he possessed and give to the poor and then follow Him, the young man went away sorrowful, for he had great possessions.
However, God promises that "everyone who has left houses or brothers or sisters or father or mother or children or lands, for my name’s sake, will receive a hundredfold and will inherit eternal life" (Matt 19:29).
So, what is God calling you to leave behind? Praise the Lord for what you have already left behind for the glorious gain of Christ.