Hadith 8:1803
Abu Bakr narrated to us, he said: Hafs bin Ghiyath narrated to us, from Ibn Jurayj, from Ibn Abi Mulaykah and 'Ata', that 'A'ishah bought a sacrificial camel, but she lost it. So she bought another in its place, then she found the first one, so she slaughtered both of them together. Then she said: "It was in the knowledge of Allah that I would slaughter both of them together." That was regarding a voluntary sacrifice.
حدثنا أبو بكر قال حدثنا حفص بن غياث عن بن جريج عن بن أبي مليكة وعطاء أن عائشة اشترت بدنة فأضلتها فاشترت مكانها ثم وجدتها فنحرتهما جميعا ثم قالت كان في علم الله أن أنحرهما جميعا ذلك في التطوع