Sayyiduna al-Bara' bin Azib (may Allah be pleased with him) narrates: "We were walking with the Messenger of Allah (peace and blessings be upon him) when he (peace and blessings be upon him) saw a group of people and asked: 'For what have these people gathered?' It was said: 'They are digging a grave.' The narrator said: the Prophet (peace and blessings be upon him) became alarmed and hurried forward from among the Companions (may Allah be pleased with them) until he reached the grave. He threw some earth on it, then sat facing it, and wept so much that the soil became wet with his (peace and blessings be upon him) tears. Then he turned to us and said: 'My brothers! Prepare for a day like this.'"
Imam al-Tabarani (may Allah have mercy on him) said: "This hadith is not narrated from al-Bara' (may Allah be pleased with him) except with this chain; Abdullah bin Waqid is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الألف / 2588
Hadith Takhrij«أخرجه ابن ماجه فى «سننه» برقم: 4195، والبيهقي فى «السنن الكبرى» برقم: 6611، وأحمد فى «مسنده» برقم: 18900، وابن أبي شيبة فى «مصنفه» برقم: 35472»