Quran 10, Yunus (Jonah) ⓘ

10:94And if thou (Muhammad) art in doubt concerning that which We reveal unto thee, then question those who read the Scripture (that was) before thee. Verily the Truth from thy Lord hath come unto thee. So be not thou of the waverers.

فَإِنْ كُنْتَ فِي شَكٍّ مِمَّا أَنْزَلْنَا إِلَيْكَ فَاسْأَلِ الَّذِينَ يَقْرَءُونَ الْكِتَابَ مِنْ قَبْلِكَ لَقَدْ جَاءَكَ الْحَقُّ مِنْ رَبِّكَ فَلَا تَكُونَنَّ مِنَ الْمُمْتَرِينَ