In Surah Bayyinah, the first three Ayahs mention how the disbelievers from the People of the Book, meaning Jews and Christians, and the people who ascribe partners in divinity to Allah, the idol worshippers from amongst the Arabs and non-Arabs, would not desist from disbelief until clear evidence would be brought to them.
The clear evidence is the purified, noble, honorable pages of the Quran from a noble messenger, peace be upon him, that was revealed directly to his, sallallahu alaihi wa sallam, heart from Allah. The clear evidence contains upright commandments, writings that are held in honor by the noble scribes, the angels of Allah. They record and note down the spoken word of the Quran so that when it is mentioned to the disbelievers, they know within their hearts that these noble writings from the Book of Allah are from Allah.
The entire different books and scrolls of revelation from Allah are upright, noble words that have been recorded in perfection, only with the angels. And the Quran is recorded in perfection with the protection from Allah. The Arabic, which is preserved, unchanged, and noble and honorable, this revelation in Arabic is clear evidence to help oneself to remove and to make people desist from disbelief. This requires regular recitation of what is possible, understanding, applying the richness in wisdom, the lessons and nobility of the words, and knowledge of the clear evidence of the Quran.