I heard the Messenger of Allah ﷺ say, "Shield yourselves from the Fire, even with half a date."
سمعت رسول الله ﷺ يقول: اتقوا النار ولو بشق تمرة.
Bukhari reported it in the chapter on zakat (1417), and Muslim in the chapter on zakat (1016), both through the route of Abu Ishaq, who said, "I heard Abdullah bin Maqil, who heard Adi bin Hatim," and he related the hadith. Both of them added, through the route of Amash, from Amr bin Mura, from Khaythama, from Adi bin Hatim, "Whoever does not find that, let him do so with a kind word." Bukhari reported it in the chapter on gentle hearts (6540), and Muslim also reported it.