Musnad Ahmad 16701

The expiation for a vow is the same as the expiation for an oath

"The expiation for a vow is the same as the expiation for an oath."

كَفَّارَةُ النَّذْرِ كَفَّارَةُ الْيَمِينِ ‏"

Narrated by Uqbah ibn ‘Āmir + 6 other versions Explained

"The Messenger of Allah said: 'There is no vow at a moment of anger and its expiation is the expiation for an oath.'"

"‏ لاَ نَذْرَ فِي غَضَبٍ وَكَفَّارَتُهُ كَفَّارَةُ الْيَمِينِ ‏"

Narrated by Imrān ibn Husayn + 7 other versions

That the Messenger of Allah (ﷺ) said: "The atonement of a vow when it is not specified is the atonement of an oath."

"‏ كَفَّارَةُ النَّذْرِ إِذَا لَمْ يُسَمَّ كَفَّارَةُ يَمِينٍ ‏"

Narrated by Uqbah ibn ‘Āmir