Musannaf Ibn Abi Shaybah 9136 — What is mentioned on the excellence

Mutarrif bin Abdullah bin al-Shikhkhir said: Once I came to Sayyiduna Uthman bin Abi al-As (may Allah be pleased with him). He called for milk of a milch she-camel for me. I said: I am fasting. He said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Fasting is a shield against the Fire just as you take a shield against the enemy in battle. A good fast is fasting three days of every month."