Sayyiduna Mahmud bin Labid (may Allah be pleased with him) said: The swords of the Muslims came upon Sayyiduna Abu Hudhayfah (may Allah be pleased with him) from different sides, and he was martyred at the hands of the Muslims themselves, while they did not recognise him. Sayyiduna Hudhayfah (may Allah be pleased with him) kept crying out: "My father! My father!" They said: "By Allah, we did not recognise him," and they spoke the truth. Sayyiduna Hudhayfah (may Allah be pleased with him) said: "May Allah forgive you, and He is the Most Merciful of those who show mercy." Then the Prophet (peace and blessings be upon him) wished to pay his blood money from himself, but Sayyiduna Hudhayfah (may Allah be pleased with him) gave it as charity to the Muslims, and that raised him further in the sight of the Messenger of Allah (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب القسامة / 16479