Qays bin Abi Hazim (may Allah have mercy on him) said: When Sayyiduna al-Ash'ath bin Qays (may Allah be pleased with him) was brought as a captive to Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him), he untied his bonds and married his sister to him. He drew his sword and entered the camel market, and he began to hamstring every camel, male or female, that he saw. People cried out: Al-Ash'ath has become a disbeliever! When he had finished, he threw down his sword and said: "By Allah, I have not become a disbeliever. Rather, this man has married his sister to me, and had we been in our own land, our wedding feast (walimah) would have been different from this. O people of Madinah, slaughter and eat! And O owners of the camels, come and take (new camels) in their place."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 645