صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب صدقة الحبوب والثمارChapters on Zakat of Grains and Fruits
(59) بَابُ احْتِسَابِ مَا قَدْ حَبَسَ الْمُؤْمِنُ السِّلَاحَ وَالْعَبْدَ فِي سَبِيلِ اللَّهِ مِنَ الصَّدَقَةِ إِذَا وَجَبَتْ، فَهَذِهِ الْمَسْأَلَةُ أَيْضًا مِنْ بَابِ تَقْدِيمِ الصَّدَقَةِ قَبْلَ وُجُوبِهَا
59| Chapter on counting what a believer has dedicated for Allah’s cause as zakat if it becomes due; this is also about paying zakat before it is obligatory
