The Messenger of Allah ﷺ mentioned the Fire and sought refuge from it, turning his face away three times. Then he said, "Guard yourselves against the Fire, even with half a date. If you cannot find that, then with a kind word."
عن رسول الله ﷺ أنه ذكر النار فتعوذ منها، وأشاح بوجهه ثلاث مرار، ثم قال: اتقوا النار ولو بشق تمرة، فإن لم تجدوا، فبكلمة طيبة.
Bukhari narrated it in al-Adab (6023), and Muslim in al-Zakat (1016: 68), both through Shuba, from Amr bin Mura, from Khaythama, from Adi bin Hatim, who related it. The wording given is Muslim's.