a disbeliever, because of his mockery. But if he does so out of negligence, the scholars differed as to whether he is to be deemed a disbeliever.
The position of Abu Hanifah (d. 150 AH) is that he becomes a disbeliever (1), because whoever prays while in a state of ritual impurity, knowing that Allah has made ablution obligatory, is like one who mocks; and mockery is disbelief, as Allah the Exalted says: “Say, ‘Was it Allah, His verses, and His Messenger that you were mocking?’” [al-Tawbah: 65–66].
The position of the other three Imams is that he does not become a disbeliever (2), because this is a sin, and it does not necessarily follow from his neglect that he is mocking.
For this reason, we say: if he prays without ablution in mockery, then he is a disbeliever; otherwise, he is not. This is closer to what is correct, because the basic principle is that one remains Muslim, and he cannot be declared outside Islam except on the basis of proof.
Second: the Sunnah:
The Prophet ﷺ said: “Allah does not accept a prayer without purification.” (3) He ﷺ also said: “There is no prayer without purification.” (4) And he ﷺ said: “Allah does not accept the prayer of any one of you when he breaks his ablution until he performs ablution.” (5)