What event happened to Abu Rafi', the merchant of Hijaz, as narrated by Al-Bara bin Azib to the Prophet Muhammad (saw)?
 Narrated Al-Bara bin Azib:                     Allah's Apostle sent a group of Ansari men to kill Abu-Rafi`. One of them set out and entered their (i.e. the enemies) fort. That man said, "I hid myself in a stable for their animals. They closed the fort gate. Later they lost a donkey of theirs, so they went out in its search. I, too, went out along with them, pretending to look for it. They found the donkey and entered their fort. And I, too, entered along with them. They closed the gate of the fort at night, and kept its keys in a small window where I could see them. When those people slept, I took the keys and opened the gate of the fort and came upon Abu Rafi` and said, 'O Abu Rafi`. When he replied me, I proceeded towards the voice and hit him. He shouted and I came out to come back, pretending to be a helper. I said, 'O Abu Rafi`, changing the tone of my voice. He asked me, 'What do you want; woe to your mother?' I asked him, 'What has happened to you?' He said, 'I don't know who came to me and hit me.' Then I drove my sword into his belly and pushed it forcibly till it touched the bone. Then I came out, filled with puzzlement and went towards a ladder of theirs in order to get down but I fell down and sprained my foot. I came to my companions and said, 'I will not leave till I hear the wailing of the women.' So, I did not leave till I heard the women bewailing Abu Rafi`, the merchant pf Hijaz. Then I got up, feeling no ailment, (and we proceeded) till we came upon the Prophet and informed him."