وَإِذَا قِيلَ لَهُمُAnd when it is said to them,means, to these people who dispute about the Oneness of Allah.اتَّبِعُوا مَا أَنزَلَ اللَّهُ"Follow that which Allah has sent down,"means, the pure Divine Laws that He has sent down to His Messengers,قَالُوا بَلْ نَتَّبِعُ مَا وَجَدْنَا عَلَيْهِ ابَاءنَاthey say:"Nay, we shall follow that which we found our fathers (following)."means, they have no other proof except the fact that they are following their forefathers.Allah says:أَوَلَوْ كَانَ ءَابَاوُهُمْ لَا يَعْقِلُونَ شَيْيًا وَلَا يَهْتَدُونَEven though their fathers did not understand anything nor were they guided. (2:170)meaning, `what do you think, you who take the forefathers' deeds as proof, that they were misguided and you are following in their footsteps!'Allah says:أَوَلَوْ كَانَ الشَّيْطَانُ يَدْعُوهُمْ إِلَى عَذَابِ السَّعِيرِEven if Shaytan invites them to the torment of the Fire