What is the wisdom behind not explicitly prohibiting masturbation in the Holy Qur’an, as is the case with adultery, to avoid doubts about its ruling, fluctuating between prohibition, permissibility, and allowance out of necessity?

Prohibiting something does not necessarily require an explicit Qur'anic text; prohibition can be established by analogy to what is explicitly stated, or by its inclusion in the generality of a text, such as the prohibition of masturbation. It falls under the generality of Allah's saying: "And those who guard their private parts Except from their wives or those their right hands possess, for indeed, they will not be blamed." Sheikh al-Islam Ibn Taymiyyah said that the clarification of rulings can be through an explicit text or through what might contain some ambiguity, and all of this is part of the clear proclamation (al-balagh al-mubeen) carried out by the Messenger of Allah, peace be upon him. He clarified everything that brings one closer to Paradise and forbade everything that brings one closer to Hellfire. Therefore, one must obey Allah's command and avoid masturbation in obedience to Him, for believers say: "We hear and we obey" when they are called to Allah and His Messenger to judge between them.