Mutarrif, from the tribe of Banu 'Amir bin Sa'sa'ah narratedthat'Uthman bin Abul-'As Ath-Thaqafi invited him to drink somemilk thathe poured for him. Mutarrif said:
"I am fasting."'Uthman said: "Iheard the Messenger of Allah (ﷺ) say: 'Fastingis a shield againstthe Fire just like the shield of anyone of youagainst fighting.'" (ID)
English reference (ID): Vol. 1, Book 7, Hadith 1639 (ID)
Arabic reference (ID): Book 7, Hadith 1708 (ID)