Ibn al-Qayyim and others have said: The default ruling concerning acts of worship is invalidity until evidence establishes that they have been commanded, for Allah is worshipped only through what He has legislated upon the tongues of His messengers.

Shaykh al-Islām likewise stated: Acts of worship are grounded in revelation and following, not in personal desire and innovation, for Islam is built on two fundamentals:
1 – That we worship none but Allah alone;
2 – And that we worship Him only with what He has legislated through the words of His Messenger ﷺ.

Shaykh ʿAbd al-Laṭīf ibn ʿAbd al-Raḥmān Āl al-Shaykh said: Know that acts of worship are strictly prescriptive, and the Lawgiver’s omission of an act despite the presence of its motive is proof that the act is to be left, just as His performance of an act is proof that it is to be done. These important maxims from those eminent imams are drawn from the Almighty’s words: “Or do they have partners who have instituted for them a religion that Allah has not authorized?” (Q 42:21) and similar verses, as well as from what is authentically reported in Muslim (1718) from ʿĀʾishah, that the Prophet ﷺ said: “Whoever does an act for which we have given no instruction, it will be rejected.”