Yunus 10:94

فَإِن كُنتَ فِى شَكٍّۢ مِّمَّآ أَنزَلْنَآ إِلَيْكَ فَسْـَٔلِ ٱلَّذِينَ يَقْرَءُونَ ٱلْكِتَٰبَ مِن قَبْلِكَ ۚ لَقَدْ جَآءَكَ ٱلْحَقُّ مِن رَّبِّكَ فَلَا تَكُونَنَّ مِنَ ٱلْمُمْتَرِينَ

If thou wert in doubt as to what We have revealed unto thee, then ask those who have been reading the Book from before thee: the Truth hath indeed come to thee from thy Lord: so be in no wise of those in doubt.