Musannaf Ibn Abi Shaybah 15042 — A man who buys a sacrificial camel

Sayyidah Aishah (may Allah be pleased with her) bought a camel, and it got lost. She bought another camel in its place, and then the first one was found again. She sacrificed both camels and said: "It was in the knowledge of Allah Almighty that I would sacrifice both of them." And that was in a voluntary sacrifice.