-->
١٣. أَمْ يَقُولُونَ ٱفْتَرَىٰهُ ۖ قُلْ فَأْتُوا۟ بِعَشْرِ سُوَرٍ مِّثْلِهِۦ مُفْتَرَيَـٰتٍ وَٱدْعُوا۟ مَنِ ٱسْتَطَعْتُم مِّن دُونِ ٱللَّهِ إِن كُنتُمْ صَـٰدِقِينَ
١٤. فَإِلَّمْ يَسْتَجِيبُوا۟ لَكُمْ فَٱعْلَمُوٓا۟ أَنَّمَآ أُنزِلَ بِعِلْمِ ٱللَّهِ وَأَن لَّآ إِلَـٰهَ إِلَّا هُوَ ۖ فَهَلْ أَنتُم مُّسْلِمُونَ
[13-14] Do they say, "He has invented the Book himself?" Say to them "Very well, if it is so, bing ten fabricated Surahs like this: and you may has been revealed with Allah's knowledge and that there is no true deity other than Allah. Do you then surrender to this (which is the very Truth)?14
14Here one and the same argument has been advanced to prove two things. First, the Qur'an has been revealed by Allah. Secondly, it proves the truth of the doctrine of Tauhid. The argument is this:
(1) "You say that the Qur'an has not been revealed by Allah but has been devised and invented by my self and ascribed to Him. If your claim had been genuine you would have been able to invent a book like this in answer to the challenge I have given you over and over again. As you have failed to do so even with your combined resources and forces, my claim that it has been revealed with Allah's knowledge has been proved absolutely, fully and completely."
(2) "Then there was a two-fold challenge from the Qur'an to your deities but they utterly failed to meet it. They were challenged to come to your aid and help produce a book like the Qur'an. As they have not helped you, it is a clear proof that they are absolutely powerless and have no share at all in Godhead. You have seen that they have not only failed in this decisive test, but have also proved to be impotent to defend themselves against the open attacks made on them in this Book, which asks the people not to worship them for they have no share in the powers of Godhead. These things have proved that there is nothing Divine in them and you have made them your deities without rhyme or reason".
Incidentally, this verse shows that chronologically this Surah was revealed earlier than Surah Yunus. For at first they were challenged in this Surah to bring ten Surahs like the Surahs of the Qur'an, but they failed to do so. Then in Surah Yunus they were challenged (v. 38) to bring even one Surah like this. (X: 38 and E.N. 46).