While the Abyssinians were playing with their spears in the presence of the Messenger of Allah ﷺ, Umar bin Khattab entered. He bent down to pick up some pebbles to throw at them, but the Messenger of Allah ﷺ said to him, "Leave them alone, Umar."
بينما الحبشة يلعبون عند رسول الله ﷺ بحرابهم، إذ دخل عمر بن الخطاب، فأهوى إلى الحصباء يحصبهم بها، فقال له رسول الله ﷺ: دعهم يا عمر.
Bukhari narrated it in Jihad and Sayr (2901), and Muslim in Eidayn (893), both of them through the route of Mamar, from Zuhri, from Ibn Musayab, from Abu Hurairah, who mentioned it, and their wording is the same. In another version, "in the masjid."