Musannaf Ibn Abi Shayba 33:1455

Ya'la ibn 'Ubayd narrated to us, he said: Isma'il ibn Abi Khalid narrated to us, he said: A famine afflicted the Children of Israel. A man passed by another man and said, "I wish that this sand were flour so that I could feed it to the Children of Israel." He said: So he was rewarded for his intention.