Sahih Muslim
The Book of Zakat (Kitab Al-Zakat)
Book Number: 005 / Hadith Number: 2218
Adi b. Hatim reported that the Messenger of Allah (may peace be upon him) made a mention of the Fire and sought refuge (with Allah against it). He turned aside his face three times and then said: Protect yourselves against Fire even if with half a date. But if you fail to find it (then protect yourselves against Fire) with the help of a pleasant word).