Ignorance as a barrier to salvation

وَلَوْ أَنَّهُمْ ءَامَنُوا۟ وَٱتَّقَوْا۟ لَمَثُوبَةٌ مِّنْ عِندِ ٱللَّهِ خَيْرٌ ۖ لَّوْ كَانُوا۟ يَعْلَمُونَ

And if they had believed and feared Allāh, then the reward from Allāh would have been [far] better, if they only knew.