Mishkat
al-Masabih
مشكاة المصابيح
Purification
كتاب الطهارة
Chapter 8c: Laws about different kinds of water - Section 3
باب المياه - الفصل الثالث
Mishkat al-Masabih 486, 487
Yahya b. Abd ar-Rahman said that ‘Umar went out with a party of riders among whom was ‘Amr b al-‘As. When they came to a cistern and ‘Amr asked its owner whether beasts of prey came down to it, ‘Umar said, “Don't tell us, owner of the cistern, for we go down to what beasts of prey leave, and they go down to what we leave.” Malik transmitted it and Razin made an addition saying that some transmitters add to ‘Umar’s words that he said he had heard Allah's Messenger ﷺ say, “They have in their bellies what they have taken, and what remains is pure for us and drinkable.”
عَن يَحْيَى بْنِ عَبْدِ الرَّحْمَنِ قَالَ: إِنَّ عُمَرَ بن الْخطاب خَرَجَ فِي رَكْبٍ فِيهِمْ عَمْرُو بْنُ الْعَاصِ حَتَّى وَرَدُوا حَوْضًا فَقَالَ عَمْرُو: يَا صَاحِبَ الْحَوْضِ هَلْ تَرِدُ حَوْضَكَ السِّبَاعُ فَقَالَ عُمَرُ بْنُ الْخَطَّابِ يَا صَاحِبَ الْحَوْضِ لَا تُخْبِرْنَا فَإِنَّا نَرِدُ عَلَى السِّبَاعِ وَتَرِدُ عَلَيْنَا. رَوَاهُ مَالك وَزَاد رزين قَالَ: زَاد بعض الروَاة فِي قَول عمر: وَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «لَهَا مَا أَخَذَتْ فِي بُطُونِهَا وَمَا بَقِي فَهُوَ لنا طهُور وشراب»
In-book reference: Mishkat al-Masabih Book 3 Chapter 8c Hadith 1