Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) narrates: Once a man called out to the Prophet (peace and blessings be upon him) three times, and each time he replied to him: "Here I am, here I am (labbayk, labbayk)."
Abu Ya'la recorded it in al-Kabir from his teacher Jubarah bin al-Mughallis, whom Ibn Numayr declared thiqah (trustworthy) and the majority declared da'if (weak); the remaining narrators of this report are thiqat (trustworthy) and are the narrators of the Sahih.