Thus, the correct view regarding this matter is also what we have mentioned: that if it is stated that he did not perform istinja with water, even though he had performed istinja with stones, then in such a case, it is recommended for him to leave the prayer while he is still engaged in it, perform istinja with water, and repeat the prayer. However, if he has already completed the prayer, then nothing is required of him. But if he had not performed istinja at all, then he would be required to repeat the prayer in any case, whether he left the prayer or not, as we have explained. And what further clarifies this is (following hadith):
Commentary #43