Salvation has no price tag; you can go to heaven even if you never give God a dime. Growth, however, often hinges on a decision to take a fundamental point of biblical commitment in giving. You determine whether the finances of this life are governed by world’s system, or the Lord’s.
This expression, found in three places in the Old Testament, refers not only to financial blessings, but also to God's releasing of growth and increase in every part of our lives. Tithing doesn't buy God's blessing, but it does open a "window" of release for Him to bless continually and mightily.