"And he said, Of a truth I say to you, that this poor widow has cast in more than they all: For all these have of their abundance cast in to the offerings of God: but she of her penury has cast in all the living that she had." (Luke 21:3-4 AKJV)
 
It's not how much we give but how much we keep that might be of the utmost value in the eyes of God.