Firstly, what Prophet Yūsuf did regarding his brothers falls under permissible tricks to prove a right or establish an argument, provided it does not undermine a fundamental religious principle or contradict a recognized interest. This is similar to uttering words of disbelief under coercion. Az-Zamakhsharī in “Al-Kashshāf” said: “… and the ruling on this deception is like the ruling on legal stratagems that are used to achieve religious benefits and interests, such as Allāh’s command to Prophet ᾽Ayyūb (peace be upon him): ‘And take in your hand a bundle and strike with it and do not break your oath.’ [Ṣād: 44] to avoid flogging her and breaking his oath. This is also similar to ᾽Ibrāhīm’s saying [about his wife]: ‘She is my sister’ to save her from the disbelieving [king]. All religious laws are but interests and ways to avoid falling into harms. Allāh has shown in this stratagem taught to Yūsuf great benefits, making it a means to achieve them, thus it was good and wonderful. Thus, it no longer falls under evil for the reasons aforementioned.”

Al-Ḥamawī, the Ḥanafī scholar, says: “Our scholars’ view is that any stratagem used by a person to invalidate another’s right or to cast doubt upon it or to evade for falsehood is disliked—prohibitively. However, any stratagem used by a person to avoid something forbidden or to achieve something permissible is good.”

Examples of permissible stratagems mentioned in the Qur᾽ān include Allāh’s command to Prophet ᾽Ayyūb: “And take in your hand a bundle and strike with it and do not break your oath. Indeed, We found him patient, an excellent servant. Indeed, he was one repeatedly turning back [to Allāh].” [Ṣād:44], which allowed him to fulfill his oath.

Similarly, the ḥadīth narrated by Sa῾īd ibn Sa῾d ibn ῾Ubādah: there was a weak man among the households who was found with one of the female slaves. Being Muslim, Sa῾d reported him to the Prophet (PBUH), who said, “Beat him with the punishment for adultery.” They said, “O Messenger of Allāh, he is too weak; if we hit him a hundred times, he will die.” The Prophet (PBUH) then said, “Take a branch with a hundred twigs, hit him once, and let him go.”

This man had committed adultery and deserved flogging, but due to his weakness, a stratagem was used for fulfilling his punishment.

Secondly, telling the truth is not obligatory at all times because testimonies vary. There is the testimony of undertaking witness and the testimony of giving witness.

The testimony of undertaking witness, for instance, occurs in contracts such as marriage, sales, and loans. These testimonies are for establishing proof, not for declaring it. On the other hand, there is the testimony given before a judge, which is the testimony of giving witness.

For the first type, it is not necessary to speak openly. For the second type, it is not permissible to withhold the truth, as Allāh says: “And do not conceal testimony, for whoever conceals it—his heart is indeed sinful.” [Al-Baqarah: 283].

Fatwa issued by Dr. Khālid Naṣr