[The Wisdom Behind Not Detailing the Rulings of Prayer in the Qur’an]

It is said in reply: Perhaps the secret and wisdom behind not detailing the rulings and limits of prayer and zakāh in the Noble Qur’an is sufficing with what Allah the Exalted knew — that the rulings and details of these two obligations would become widely known among the Muslims and spread among them in such a manner that no obscurity would attach to them until the end of legal responsibility.
If it is said: Many disagreements have occurred within the Ummah regarding the details of the rulings of these two obligations. Had their rulings and details been mentioned in the Qur’an, such disagreement would not have occurred, just as much disagreement did not occur regarding the obligations of fasting and Hajj.
It is said in reply: The occurrence of disagreements in some details of the rulings of these two obligations does not harm the essence of the obligation nor the duty to perform it.
Consensus and agreement have occurred regarding their essential details that are indispensable. As for what disagreement has occurred in these two obligations, it is not from their pillars nor from their fundamental components. Thus, disagreement in such matters is disagreement outside the essence of the obligation; it does not harm it, nor does ignorance of it cause harm.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.3