Musannaf Ibn Abi Shayba 7:193

Al-Fadl ibn Dukayn narrated to us, from Muhammad ibn Talha, from Hammad, from Ibrahim: It is the same for a man to say "I swear," or "I swear by Allah," or "Upon me is a Hajj," or "A Hajj is upon me," or "Upon me is a vow to Allah."