What is the authenticity and meaning of the hadith: “Whoever introduces a good practice…”?

Q: Is this a hadith? And if it is a hadith, did the Messenger (peace and blessings be upon him) leave anything for anyone to introduce as a practice in Islam? We ask you to clarify this matter for us in detail.

A: This hadith is authentic, and it indicates the legitimacy of reviving the Sunnah, calling people to it, and warning against religious innovations and evils; because he (peace and blessings be upon him) said: It was narrated by Muslim in his Sahih.
Similar to this hadith is what Abu Hurayrah (may Allah be pleased with him) narrated from the Prophet (peace and blessings be upon him) that he said: And similarly, the hadith of Abu Mas'ud al-Ansari (may Allah be pleased with him) , in which the Prophet (peace and blessings be upon him) said: Muslim narrated both of them in his Sahih.
The meaning of “introducing” in Islam is: reviving a Sunnah, making it apparent, and highlighting it from what may be hidden from people, so he calls people to it, makes it apparent, and explains it. Thus, he receives a reward like the rewards of those who follow him in it. It does not mean innovating in the religion; because the Messenger (peace and blessings be upon him) forbade innovations and said: And his words (peace and blessings be upon him) are consistent with one another and do not contradict one another, by the consensus of the scholars. Therefore, it is known that the intended meaning of the hadith is reviving the Sunnah and making it apparent. An example of this is: a scholar in a certain land where there is no teaching of the Noble Qur'an or no teaching of the Prophetic Sunnah. He revives this Sunnah by sitting with people to teach them the Qur'an and teach them the Sunnah, or by bringing in teachers. Or in a land where they shave their beards or trim them, he commands them to let the beards grow and let them hang down. By doing so, he has revived this great Sunnah in this land that did not know it, and he will have a reward like the reward of those whom Allah guided through his means.
And the Messenger (peace and blessings be upon him) said: It is agreed upon as authentic from the hadith of Ibn 'Umar (may Allah be pleased with them both). When the people saw this scholar had let his beard grow and called to that, they followed him, so he revived the Sunnah through them. It is an obligatory Sunnah that it is not permissible to leave, in accordance with the mentioned hadith and what came in its meaning. Thus, he will have a reward like their rewards.
It may be that in a land, people are ignorant of the Friday prayer and do not perform it, so he teaches them and prays Friday with them, and he will have a reward like their rewards. And similarly, if he is in a land where people are ignorant of the Witr prayer, he teaches them and they follow him in that, or similar matters of worship and rulings known from the religion. Ignorance of them may arise in some lands or some tribes. The one who revives them among them, spreads them, and explains them is said to have “introduced a good practice in Islam,” meaning that he made the ruling of Islam apparent. By doing so, he is among those who introduced a good practice in Islam. It is not intended that one should innovate in the religion what Allah has not permitted, for all innovations are misguidance, due to the saying of the Prophet in the authentic hadith: And he (peace and blessings be upon him) said in the authentic hadith also: And in the other wording: It is agreed upon.
And he said in the Friday sermon, peace and blessings be upon him: “As for what follows:” It was narrated by Muslim in his Sahih.
Therefore, the worship that Allah has not prescribed is not permissible to call people to, and its practitioner is not rewarded. Rather, his doing it and calling to it is among the innovations, and by that, the one calling to it is among those who call to misguidance. And Allah has criticized those who do that by His saying, Exalted is He: The verse [Surah al-Shura: 21].