An-Nahl • EN-ASBAB-AL-NUZUL-BY-AL-WAHIDI
﴿ وَإِذَا بَدَّلْنَآ ءَايَةًۭ مَّكَانَ ءَايَةٍۢ ۙ وَٱللَّهُ أَعْلَمُ بِمَا يُنَزِّلُ قَالُوٓا۟ إِنَّمَآ أَنتَ مُفْتَرٍۭ ۚ بَلْ أَكْثَرُهُمْ لَا يَعْلَمُونَ ﴾
“And now that We replace one message by another -since God is fully aware of what He bestows from on high, step by step - they [who deny the truth] are wont to say, "Thou but inventest it!" Nay, but most of them do not understand it!”
(And when We put a revelation in place of (another) revelation�) [16:101-102]. This verse was revealed when the idolaters said: �Muhammad is mocking his Companions; one day he commands them to do something and the next day he forbids them from doing it, or brings instead something which is easier. He is nothing but a calumniator who says things of his own invention�, and so Allah, exalted is He, revealed this verse and the verse after it.