Sahih al-Bukhari 6959
Narrated Ibn Abbas:
Sa'd bin 'Ubada Al-Ansari sought the verdict of Allah's Messenger (ﷺ) 
     regarding a vow made by his mother who had died before fulfilling it. 
     Allah's Messenger (ﷺ) said, "Fulfill it on her behalf." Some people said, 
     "If the number of camels reaches twenty, then their owner has to pay 
     four sheep as Zakat; and if their owner gives them as a gift or sells 
     them in order to escape the payment of Zakat cunningly before the 
     completion of a year, then he is not to pay anything, and if he 
     slaughters them and then dies, then no Zakat is to be taken from his 
     property."
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّهُ قَالَ اسْتَفْتَى سَعْدُ بْنُ عُبَادَةَ الأَنْصَارِيُّ رَسُولَ اللَّهِ صلى الله عليه وسلم فِي نَذْرٍ كَانَ عَلَى أُمِّهِ، تُوُفِّيَتْ قَبْلَ أَنْ تَقْضِيَهُ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ اقْضِهِ عَنْهَا ‏"‏‏.‏ وَقَالَ بَعْضُ النَّاسِ إِذَا بَلَغَتِ الإِبِلُ عِشْرِينَ، فَفِيهَا أَرْبَعُ شِيَاهٍ، فَإِنْ وَهَبَهَا قَبْلَ الْحَوْلِ أَوْ بَاعَهَا، فِرَارًا وَاحْتِيَالاً لإِسْقَاطِ الزَّكَاةِ، فَلاَ شَىْءَ عَلَيْهِ، وَكَذَلِكَ إِنْ أَتْلَفَهَا فَمَاتَ، فَلاَ شَىْءَ فِي مَالِهِ‏.‏