An ass asked a horse for a little barley. "With all my heart," Said he, "If I had more than I wanted, I would give you plenty, in accordance with my dignified position; but bye-and-bye, as soon as I shall have come to my manger in the evening, I will give you a sackful of wheat." The ass replied: "If you now deny me on a trifling occasion, what am I to suppose you will do on one of greater importance?" 
They who, while making great promises, refuse small favours, show that they are very tenacious of giving. 