Mustadrak al-Hakim — Hadith 4363

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that Amr bin Uqaysh was owed some usury (riba) from the Days of Ignorance, and this very usury was preventing him from accepting Islam, so that he could first collect it and then accept Islam. One day he came while the Messenger of Allah (peace and blessings be upon him) and his Companions were at Uhud. He asked: Where is Sa'd bin Mu'adh? He was told: At Uhud. Then he asked: Where are his nephews? He was told: At Uhud. Then he inquired about his own people, and they said that they too were at Uhud. So he took his sword and spear, put on his armor and set out for Uhud. When the Muslims saw him, they said: O Amr! Keep away from us. He replied: I have believed. Then he charged with full force and fought, until he was carried back to his family wounded. Sayyiduna Sa'd bin Mu'adh came to him and asked him: Did you come out of anger for the sake of Allah and His Messenger, or out of tribal zeal and honor for your people? He replied: Rather, I came out of anger for the sake of Allah and His Messenger. Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: He entered Paradise, although he had not prayed a single prayer for Allah.
This hadith is sahih (authentic) on the condition of Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.