Musnad Ahmad 5:127

Hashim ibn al-Qasim narrated to us, Isra'il narrated to us, from Jabir, from Muhammad ibn Ali, from his father, from Ali, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "I have made a vow to slaughter my she-camel, and such and such." He said: "As for your she-camel, slaughter it; and as for such and such, it is from Satan."