What is the ruling on dealing with the group "Ahl al-Qur'an" who claim the special significance of the number "nineteen" in Islamic Sharia, and are they considered Muslims?

The mentioned number has no religious significance. The group that emerged in the Indian subcontinent, known as "Ahl al-Qur'an," is a misguided group that advocates for taking only the Qur'an and denying the Sunnah. This group is an extension of the Rawafid (Shi'ites) and Khawarij, who adhered to the apparent meaning of the Qur'an and abandoned the Sunnah, which clarifies the Book, leading to their misguidance. Allah has enjoined obedience to His Messenger in many verses, such as: "And whatever the Messenger has given you - take it; and what he has forbidden you - refrain from it" and "It is not for a believing man or a believing woman, when Allah and His Messenger have decided a matter, that they should have [any] option in their decision." Allah also says: "And We revealed to you the message that you may make clear to the people what was sent down to them." The Messenger of Allah (peace be upon him) said: "Indeed, I have been given the Qur'an and something similar to it with it," and this is a refutation of those who suffice with the Qur'an without the Sunnah. The Prophetic Sunnah clarifies the general meanings of the Qur'an, as in the details of prayers, zakat, and Hajj, and as reported by Jabir ibn Abdullah concerning Hajj: "And the Messenger of Allah was among us, and the Qur'an was being revealed to him, and he knew its interpretation, so whatever he did, we did." The Companions and their followers emphasized that the Sunnah explains and clarifies the Qur'an. Indeed, 'Imran ibn Husayn refuted those who denied the Sunnah by stating that the details of prayer and zakat are not found in the Qur'an except through the Sunnah. Mak'hul said: "The Qur'an is more in need of the Sunnah than the Sunnah is of the Qur'an." It is necessary to be wary of associating with these misguided groups or going to their mosques, and to advise those who advocate for them with the presented evidence.