Narrated Thabit bin Lahhak (ra) : In the time of the Prophet (sal) a man took a vow to slaughter a camel at Buwanah. So he came to the Prophet (sal) and said: I have taken a vow to sacrifice a camel atBuwanah. The Prophet (sal) asked: Did the place contain any idol worshipped in pre-Islamic times? They (the people) said: No. He asked: Was any pre-Islamic festival observed there? They replied: No. The Prophet (sal) said:Fulfil your vow, for a vow to do anact of disobedience to Allah must not be fulfilled, neither must one do something over which a human being has no control. [AbuDawud 2881