عَنْ عُقْبَةَ بْنِ عَامِرٍ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِنَّمَا النَّذْرُ يَمِينٌ كَفَّارَتُهَا كَفَّارَةُ الْيَمِينِ
It is narrated from Sayyiduna Uqbah bin Amir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: A vow is indeed an oath, therefore its expiation is the same as the expiation for an oath.