Literally, the word in Arabic comes from the root verb meaning to introduce, invent, or create. Usually, bidʿa is translated as “innovation,” and often comes to have the negative connotation of heresy. That is, they denote something not done by the Prophet ﷺ and therefore be heretical.
Just at first glance, there are many things we do today that the Prophet ﷺ never did, such as riding a car or turning on the air conditioning. Can these “innovations” be classified as heretical simply because they did not exist during the time of the Prophet ﷺ? How do we judge the developments in our age, not just of technology, but of devotional practices?
When it comes to Islamic rulings on these matters, the concept of bidʿa is more complicated and there exists more complex dimensions that affect its meanings. There are “good innovations” and “bad” ones. Thus, the first step to answering this question is to understand the classification of a bidʿa.
In a ḥadith in Sahih Muslim, the Prophet ﷺ is reported to have said, “whoever inaugurates a good custom, he shall have the reward of all who follow him in it thereafter, without this decreasing anything of their own reward. And whoever inaugurates an evil custom in Islam shall bear the sin for it without this decreasing anything of their own sins.”
In this ḥadīth, the Prophet ﷺ makes a distinction between a newly inaugurated practice that is blameworthy and one that is praiseworthy. The ʿulamāʾ interpret this to mean that not every new development in Islam is bad. Imam al-Shāfiʿī, for example, explains it in the following way:
Newly inaugurated matters are of two categories: 1) something newly inaugurated that contravenes the Quran or the Sunna, the position of the Sahaba (athar), or the Ijmāʾ (the unanimous concession of the Umma). This is a bidʿa of misguidance. 2) Or that which is inaugurated of something good, in which there is nothing that contravenes any of these things (i.e., the Quran, Sunna, Ijmāʾ, and athar) . Umar [Ibn al-Khattab] has said regarding the tarawih in Ramadan, ‘what a great bidʿa this is!’ Meaning that it was something newly begun that didn’t previously exist.”
Another great scholar who lived much later after Imam al-Shafiʿī, Izz al-Din Ibn ʿAbd al-Salam, comments on his position, saying that we have to decide whether or not new matters contravene or conform to Sacred Law. this means that all new matters are subject to the five rulings of the Sacred Law: Permissible, impermissible, obligatory, recommended, and disliked.
Given these opinions, which scholars share, we can think of many things that are technically “innovations,” but are, in fact, praiseworthy. A good example of this is the musḥaf. While the Quran was written down during the time of the Prophet ﷺ, it was only collected as a book later, under the imperative of his Companions. Even though this was an innovation, no one would disagree that it was a praiseworthy one. There are many more examples, such as madrasas that teach people the din, or scholarships, or a multitude of things that benefit the umma today but which didn’t exist during the lifetime of the Prophet ﷺ.
To summarize: Every single action or “innovation” is classified according to whether or not it is attested to in the Quran and Sunna, even in a general way. Determining this is a task for the fuqahaʾ.