It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) sent Sayyiduna Amr bin al-Tufayl (may Allah be pleased with him) towards Khaybar to bring reinforcements from his people, and said: "O Amr, go and bring us reinforcements from your people." Sayyiduna Amr said: O Messenger of Allah, are you sending me at a time when the fighting has broken out? The Messenger of Allah (peace and blessings be upon him) said: "Are you not pleased to be the envoy of the Messenger of Allah (peace and blessings be upon him)?"
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7851