Throughout Scripture and time, God has always had a test. Because of Lucifer's cosmic, rebellion, God placed a test of loyalty in the Garden of Eden -- the Tree of Knowledge of Good and Evil. Adam and Eve could eat of every tree except the one that was holy unto the Lord. After their fall, tithe became mankind's test of loyalty. "A tithe... belongs to the Lord; it is holy to the Lord" (Leviticus 27:0 NIV). This continues to be a test of loyalty with tithe returned to God for funding local, regional and worldwide ministry.
Stewards return tithe as an expression of their faithfulness to God, and it is part of their relationship with Him.