Section: If he witnesses an act and then becomes blind, it is permissible for him to testify regarding it if he knows the person against whom he is testifying by his name and lineage. Al-Shafi'i stated this. Abu Hanifa said: His testimony is not permissible at all, because it is not permissible for him to be a judge. Our evidence is what has preceded, and because blindness is the loss of a sense that does not impair legal responsibility (taklif), so it does not prevent the acceptance of testimony, like deafness. It differs from the office of judge, for there are conditions of perfection required for it that are not required for testimony, and for this reason, hearing and legal reasoning (ijtihad) and other qualities are required for it. If he does not know the person against whom he is testifying by his name and lineage, but is certain of his voice due to frequent association with him, it is permissible for him to testify to it as well, for the reasons we mentioned at the beginning of the issue. If he testifies before the judge and then becomes blind before the judgment is passed based on his testimony, the judgment is permissible. Al-Shafi'i, Abu Yusuf, and Muhammad stated this. Abu Hanifa said: Judgment based on it is not permissible, because it is a condition that prevents the acceptance of testimony while speech remains intact, so it prevents judgment based on it, like immorality (fisq). Our evidence is that it is a condition that occurred after the performance of the testimony and does not give rise to suspicion regarding the time of the testimony, [so it does not prevent its acceptance, like death, and it differs from immorality, for that gives rise to suspicion at the time of the testimony] (7).

Section: The testimony of a mute person is not permissible under any circumstances. Ahmad, may Allah be pleased with him, stated this explicitly, saying: The testimony of a mute person is not permissible. It was said to him: Even if he writes it down? He replied: I do not know. This is the view of the scholars of opinion (ashab al-ra'y). Malik, al-Shafi'i, and Ibn al-Mundhir said: It is accepted if his sign language is understood, because it stands in the place of his speech in his legal matters, such as his divorce, marriage, zihar, and ila', so it is the same for his testimony. Ibn al-Mundhir provided evidence that the Prophet (peace be upon him) gestured while he was sitting in prayer to the people while they were standing, for them to sit down, and they sat down (8). Our evidence is that it is testimony by gesture, so it is not permissible, like the gesture of a speaking person. This is confirmed by the fact that certainty is required in testimony, and for this reason, the indication of a speaking person is not sufficient, and certainty is not obtained through gesture. It is only considered sufficient (9) by his gesture in his own specific legal matters out of necessity, and there is no necessity here. For this reason, it is not permissible for him to be a judge, and because a judge does not execute a ruling if he finds the ruling in his own handwriting under his seal without him mentioning his ruling, and a witness does not testify by seeing his own handwriting; therefore, preventing him from ruling by someone else's handwriting is more appropriate. What Ibn al-Mundhir used as evidence is not correct, for the Prophet (peace be upon him) was capable of speech.