God is generous and so He calls us to be as well. We want to glorify God with every area of our lives, and that includes what we do with our finances. God also promises to bless us:
Give, and it shall be given unto you; good measure, pressed down, and shaken together, and running over, shall men give into your bosom. For with the same measure that ye mete withal it shall be measured to you again. Luke 6:38