Why did God allow the distortion of the Gospel despite His ability to preserve it, and what were the teachings that Muslims followed before the advent of Prophet Muhammad (peace be upon him)?

God entrusted the preservation of the Torah and the Gospel to their scholars and monks. He did not undertake their preservation Himself, as He did with the Quran. Therefore, among the wisdoms behind this are: 1. God willed for the Quran to remain the eternal book and the everlasting law until the Day of Judgment, as it is a guardian over the previous scriptures. 2. To make it a test for the People of the Book regarding its preservation, their belief in what it contains, and their following of the unlettered Prophet. 3. To make it an affliction for the followers of the Christian religion, for they see their book as corrupted or doubted, while they see the Quran as preserved, which calls them to believe in the Holy Quran.

People during the pre-Islamic era (Jahiliyyah) were immersed in polytheism and idolatry. A few of them followed the law of Christ or were Hanifs adhering to the religion of Abraham, such as Waraqa ibn Nawfal and Zayd ibn Amr ibn Nufayl, who avoided polytheism, prostrated to the One God, refused to eat what was slaughtered for idols, and saved the buried infant girls (mau'udah).