Proverbs 3:9-10
Honor the Lord with your wealth and with the first fruits of all your produce; then your barns will be filled with plenty, and your vats will be bursting with wine.
(When we choose to give back to God first the tithe we acknowledge everything we have comes from Him; thus our money will be blessed as God meets our needs when He is given our first fruits.
When we don't, we're being unwise & ultimately we're robbing God.)