You cannot give what you do not eat to the poor
 

One of his friends gave him a lizard (a creature living in the desert) to him as a gift to eat. However, He did not eat lizard since he was not accustomed to it. Hz. Aisha, who knew this, asked his permission to give the lizard to the poor person asking for something to eat at that moment. He did not permit:

“-You cannot give the poor what you do not eat.”