God calls us to give back to him 10% of our income, called the TITHE.  This is the only place in scripture where God tells us to test Him:

“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 there will not be enough room to store it” – Malachi 3:10

If we trust in God’s goodness, we will trust Him in every area of our life.  Step out in faith and test Him and witness what God does in and through your life.