God uses the tithe as an investment where everyone involved gets a return. If we are blessed beyond our needs, it is not for the purpose of living more lavishly, but rather to bless others. The church and the kingdom are blessed, and yet God's nature is to also bless the giver.
What do the scriptures say about giving?
Malachi 3:10 states, "Bring the whole tithe into the storehouse, that there may be food in my house. Test me in this, says the LORD Almighty, and see if I will not throw open the floodgates of heaven and pour out so much blessing that you will not have room enough for it." Giving our tithes and offerings reflects a grateful heart that wants to give back to God a portion of what He has given us; in reality, what is already His. This is our opportunity to show God that He is first in our lives.
James 1:17 says that "every good and perfect gift is from above...," so we have an opportunity to tangibly show God that He is the "owner" of our finances by giving back to Him the first of what He gives us.
2 Corinthians 8:7 says, "But just as you excel in everything - in faith, in speech, in knowledge, in complete earnestness and in your love for us - see that you also excel in this grace of giving."