One Who Believes a Qādhif is also a Qādhif

Shaikh Muḥammad Al-Amīn Al-Shinqīṭī, may Allāh have mercy on him, said:

The more obvious to me [in correctness] of the two sayings of the people of knowledge in the issue of a man–if he were to qadhafa¹ another man, and then another [person] said [to the qādhif²], “You’ve said the truth”–is that the one who believed [the qādhif] is a qādhif [just like him]; it is then a binding obligation to establish the [Sharīʿah] punishment [for qadhf] on [this person who believed the original qādhif was telling the truth].

¹defaming someone by attributing fornication or homosexuality to him without producing four witnesses to the act as required by Islamic law (trans.)
²the one doing qadhf, i.e., engaging in this kind of defamation (trans.)

Aḍwāʾ Al-Bayān, vol. 6, p. 111.