Luke 16:10

He who is faithful in a very little thing is also faithful in much; and he who is dishonest in a very little thing is also dishonest in much.

It is important to have integrity of the heart. God will not entrust something important to His kingdom to someone who cannot be faithful to His Word. A wicked heart will not be honest in its dealings. Jesus came to change the sinner, remove the sin from the heart, and turn the dishonest person into an honest one.