This proverb teaches us the importance of the continued economy, although it is small things. Actually it is composed by two sayings, in the opposite sense. The first part: “a grain does not make barn” serves to warn us that something is a smallness.But, with the addition, invites not to underestimate small things, if they are not enough by themselves , at least they are part to get something more important. Like the sand on the beach, a grain of sand does not do anything but if you add it together it makes a beach. Then, the second part is a response to the first.