There’s no one verse for it, but it’s a clear biblical principle.  When people give a little God can do a lot! Little David came with himself and 5 stones.  A woman gave her last bit of oil. The disciples were commanded to take nothing.  Nothing.  A little boy came forward with 5 loaves and 2 fish. Each time they gave enough.  Each time God did a lot.  Each time God did a miracle.  Each time God gave a firsthand experience.