Muhammad ibn al-Hanafiyyah (may Allah have mercy on him) said: I saw Sayyiduna Abu Amr al-Ansari (may Allah be pleased with him), who was a Companion who had attended Badr, al-Aqabah and Uhud. He was fasting and writhing from the intensity of thirst, and he was saying to a slave of his: Woe to you, shield me. So the slave shielded him, until he drew an arrow weakly, until he had shot three arrows. Then he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever shoots an arrow in the path of Allah, whether it falls short or reaches its target, it will be a light for him on the Day of Resurrection." Then it was reported that he was martyred at sunset.
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19154