Faith without works is dead.
Believing that Jesus made it possible to become part of the kingdom of heaven is manifest by performing the works necessary to lay up treasure in heaven. Men who never stop laying up for themselves treasures on earth never start laying up treasures in heaven.
When Jesus returns bringing His reward with Him, He will bring no reward for those who laid no treasure up in heaven.
Heaven treasures mercy. Those who never show mercy will be judged without mercy.