Someone may say: 'There are innovated things which the muslims have accepted and have acted upon yet these things were not known during the time of the Messenger (sallallaahu alayhi wasallam) such as schools, composition of books and whatever resembles that. These are innovations which the muslims have considered to be good, acted upon them and see them as being from the best of actions. How then can you reconcile between this which is almost unanimously agreed upon by the muslims and between the speech of the leader of the muslims, the prophet of the muslims and the Messenger of the Lord of all the Worlds (sallallaahu alayhi wasallam) : "Every innovation is misguidance."
The answer: We say that this in reality is not an innovation. Rather it is a means to something which has been legislated (in the Sharee'ah). The means differ from place to place and time to time. It is from the established principles (in the Sharee'ah) that the means have rulings related to their intent or purpose. Therefore, ways and means for achieving something legislated are also legislated and permissible. Means and ways for things which are not legislated are also not legislated and means and ways to things which are unlawful are forbidden. Even good, when it is a means towards evil is also evil and as such is forbidden. Listen to the words of Allaah Azzawajall:
And do not revile or curse those whom they call
upon besides Allaah so that they also revile and curse Allaah out of enmity
Reviling the gods of the pagans is not wrong rather it is true and justified however reviling the Lord of all the Worlds is improper, unjustified and constitutes enmity and oppression. That is why when the praiseworthy reviling of the gods of the pagans is a clear and open cause for reviling the Lord of all the Worlds it is unlawful and prohibited. I have presented this as a proof to show that the ways and means have rulings related to their intent and purpose. Therefore, schools, writing down of knowledge and authorship of books while they may be innovations, not being found in the era of the Prophet (sallallaahu alayhi wasallam) in this manner, are not the sole intent and purpose (i.e. sought in themselves). Rather they are of the means and ways which have the same ruling as the intent and purpose behind them, which in this case is to teach and spread knowledge.
This is why if a person was to build a school for the purposes of teaching knowledge which is forbidden, the building of the school is also forbidden and if he was to build the school for the purposes of teaching the Sharee'ah the building of this school is legislated and would be permissible.
If one was to say: How would you respond to the saying of the Prophet (sallallaahu alayhi wasallam) : "Whoever enacted in Islaam a good sunnah would have its reward and the reward of whoever acted upon it till the day of Judgement."
The answer: The one who said: "Whoever enacted in Islaam a good sunnah..." is the same one who said: "Every innovation is misguidance" and it is not possible that a saying should arise from the truthful and believed one (the Messenger) which makes another of his sayings false. It is not possible that the words of the Messenger of Allaah (sallallaahu alayhi wasallam) should ever contradict. Nor is it ever possible to reject one meaning when there is a contradiction. Whoever thinks that the words of Allaah or the words of His Messenger (sallallaahu alayhi wasallam) are contradictory should look again. This suspicion only arises either out of incapability or negligence. It is not possible for a contradiction to be found in the words of Allaah the Exalted or the words of His Messenger (sallallaahu alayhi wasallam) .
When that is the case the explanation of the lack of contradiction between the hadeeth: "Every innovation is misguidance" and the hadeeth: "Whoever enacted in Islaam a good sunnah" is that the Prophet (sallallaahu alayhi wasallam) said: "Whoever introduced in Islaam" and innovations are not from Islaam. He also said: "hasanah (good)" and innovation is not hasanah (good). There is also a difference between reviving and innovating.
There is also another answer in which there is no fault: That the meaning of "man sanna (whoever enacted)" is: Whoever revived a sunnah which used to exist and then it became non-existent (disappeared). Built upon this, "enacting" is a relative addition just like when one revives a sunnah after it had been abandoned is considered as an innovation (in relation to its previous non-existence).