It is narrated from Yahya bin Abd al-Rahman bin Hatib (may Allah have mercy on him) that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) set out with a caravan, and among them was Sayyiduna Amr bin al-As (may Allah be pleased with him). When they came to a watering trough, Sayyiduna Amr bin al-As (may Allah be pleased with him) said to the owner of the trough: O owner of the trough! Do beasts of prey come to your trough? Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said: O owner of the trough! Do not tell us, for beasts of prey come to us and we come to them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1181