وَعَنِ ابْنِ عَبَّاسٍ
أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَنْ نَذَرَ نَذْرًا لم يسمه فَكَفَّارَتُهُ كَفَّارَةُ يَمِينٍ. وَمَنْ نَذَرَ نَذْرًا لَا يُطِيقُهُ فَكَفَّارَتُهُ كَفَّارَةُ يَمِينٍ. وَمَنْ نَذَرَ نَذْرًا أَطَاقَهُ فَلْيَفِ بِهِ»
Ibn Abbas reported God’s Messenger as saying, “If anyone takes a vow but does not name it, its atonement is the same as that for an oath; if anyone takes a vow to do an act of disobedience, its atonement is the same as that for an oath; if anyone takes a vow he is unable to fulfil, its atonement is the same as that for an oath; but if anyone takes a vow he is able to fulfil, he must do so.”
Mishkat al-Masabih 3302, Book 16, Oaths and Vows, Hadith 30. 1 min read