فَإِن لَّمْ يَسْتَجِيبُوا لَكَBut if they answer you not,means, `if they do not respond to what you tell them, and do not follow the truth,'فَاعْلَمْ أَنَّمَا يَتَّبِعُونَ أَهْوَاءهُمْthen know that they only follow their own lusts.means, with no basis or evidence. وَمَنْ أَضَلُّ مِمَّنِ اتَّبَعَ هَوَاهُ بِغَيْرِ هُدًى مِّنَ اللَّهِAnd who is more astray than one who follows his own lusts, without guidance from Allah,means, with no guidance taken from the Book of Allah.إِنَّ اللَّهَ لَا يَهْدِي الْقَوْمَ الظَّالِمِينَVerily, Allah guides not the people who are wrongdoers