It is narrated from Sayyiduna Labibah (may Allah be pleased with him) that whenever the Messenger of Allah (peace and blessings be upon him) recited this verse: "How then will it be when We bring from every nation a witness, and bring you as a witness over all these?" [Surah al-Nisa': 41], the Messenger of Allah (peace and blessings be upon him) would weep and say: "O my Lord! I bear witness over those among whom I have lived, so what of those whom I have not even seen?"
Hadith Referenceالمعجم الكبير للطبراني / باب اللام / 16541