A similar tradition has also been transmitted by 'Uqbah b. 'Amir from the Prophet (ﷺ) through a different chain of narrators.
Sunan Abi Dawud Book 22, Hadith 83
← Previous Hadith The Messenger of Allah (ﷺ) as saying: The atonement for a vow is the same as for an oath.

Abu Dawud said: This tradition has also been transmitted by 'Amr b. al-Harith from Ka'b b. 'Alqamah, from Ibn Shamasah on the authority of 'Uqbah.

Sunan Abi Dawud Book 22, Hadith 82 Next Hadith → That 'Umar said: Messenger of Allah, I took a vow in pre-Islamic times that I would stay in the sacred mosque (Masjid Haram) as a devotion (i'tikaf). The Prophet (ﷺ) said: Fulfill your vow.

Sunan Abi Dawud Book 22, Hadith 84