It is more blessed to give than to receive.
— Acts 20:35
There are in the Scripture some 72 different passages which deal with giving, and of those, some 48 passages describe the distinct and open promises of the special blessings of God upon those who give.
I believe that the motive for giving should be gratitude to God for what He has already given to us. We should give for the purpose of advancing His glory and His kingdom in the world. The additional blessings He pours out upon us are simply super-abounding blessings that He gives above everything else He has given.
Those who tithe find that they are no worse off than they were before, but rather that God has blessed them, as He said, and opened the windows of Heaven to them. They are amazed to discover that God has provided all of their needs out of His abundance, and that the nine-tenths goes farther than the ten-tenths.
To live a generous life is to imitate God. As we give much, God blesses us even more.