Abu Dawud
Oaths and Vows
Book Number: 015 / Hadith Number: 3299
Narated By Jabir ibn Abdullah : A man stood on the day of Conquest (of Mecca) and said: Apostle of Allah, I have vowed to Allah that if He grants conquest of Mecca at your hands, I shall pray two rak'ahs in Jerusalem.
He replied: Pray here.
He repeated (his statement) to him and he said: Pray here.
He again repeated (his statement) to him.
He (the Prophet) replied: Pursue your own course, then.