[Abu 'Eisa said:] This Hadith is Hasan Sahih, and there is something on this topic from Ibn 'Umar.
In-book : Book 23, Hadith 15
English translation : Vol. 3, Book 21, Hadith 1684
23. The Book on Jihad
باب مَا جَاءَ فِي الاِسْتِنْجَاءِ بِالْحَجَرَيْنِ