حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ رَافِعٍ، عَنْ خَالِدِ بْنِ يَزِيدَ، عَنْ عُقْبَةَ بْنِ عَامِرٍ الْجُهَنِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ ‏"‏ مَنْ نَذَرَ نَذْرًا وَلَمْ يُسَمِّهِ فَكَفَّارَتُهُ كَفَّارَةُ يَمِينٍ ‏"‏ ‏.‏
Translation
lt was narrated from Ibn 'Abbas that the Prophet (ﷺ) said

"Whoever makes a vow and does not state it specifically, the expiation (for such a vow) is the expiation for breaking an oath. Whoever makes a vow and is not able to fulfill it, the expiation for that is the expiation for breaking an oath. Whoever makes a vow and is able to fulfill it, let him do so."