Joy comes from blessing others. This does not mean that it comes from you. It comes from Him. If it comes from you, one of several things will happen. You cannot bless or give endlessly, because you are not giving from an endless source. You may have resentment or bitterness around the giving, because you may feel an obligation to do it, like this is what God wants you to do. And you may be giving to be recognized for it, which is an ego need. When you truly get out of the way and become a clear vessel through which He can bless and give to others, you can do this without end, and you derive the greatest joy, because it is His joy.