and Muḥammad [ibn al-Ḥasan] said that the judge must investigate the witnesses both in private and in public.

The evidence a witness may bear falls into two categories:

1. Matters whose legal effect is established by their very occurrence—such as a sale, a confession, usurpation, homicide, or a judicial verdict. If the witness hears or sees any of these, he may testify to it even though he was not formally called to witness it, and he should say, “I testify that he sold,” not, “He made me a witness.”

2. Matters whose effect is not established on their own, such as testimony regarding another person’s testimony. If he hears someone testifying to something, it is not permissible for him to testify to that witness’s statement unless the original witness expressly appoints him. Likewise, if he hears a witness testifying to the testimony of yet another witness, the listener may not testify.

A witness who merely recognizes his own handwriting may not lawfully testify unless he also remembers the testimony itself.

Inadmissible testimony includes that of a blind person, a slave, anyone punished for slanderous accusation of fornication—even after repentance—a father for his child or grandchild, a child for his parents or grandparents, one spouse for the other, a master for his slave or mukātib, and a partner for his partner concerning their joint property. By contrast, a man’s testimony in favor of his brother or paternal uncle is accepted.

Also rejected is the testimony of an effeminate man (mukhannath), a professional mourner (nā’iḥah), a female singer, a habitual drinker given to amusement, someone who entertains himself with birds, or anyone who sings to the public. The same applies to anyone who commits a major sin that entails a ḥadd penalty, enters a bathhouse unclothed, consumes usury, gambles with dice (nard) or chess, or engages in frivolous acts such as urinating or eating in the public thoroughfare.

The testimony of one who openly reviles the early generations (al-salaf) is not accepted, whereas the testimony of sectarians (ahl al-ahwāʾ) is accepted—except for the Khattābiyyah sect.

Protected non-Muslims (ahl al-dhimmah) may testify against one another even if they belong to different religions, but the testimony of a hostile non-Muslim (ḥarbī) against a dhimmī is not accepted.

If a man’s good deeds outweigh his misdeeds and he avoids the major sins, his testimony is accepted even though he may occasionally fall into a minor sin.

The testimony of an uncircumcised man is accepted, as is that of a eunuch, a child born out of wedlock, and an intersex person (khunthā).

When the testimony coincides