﴿ فَإِن كَذَّبُوكَ فَقُل رَّبُّكُمْ ذُو رَحْمَةٍۢ وَٰسِعَةٍۢ وَلَا يُرَدُّ بَأْسُهُۥ عَنِ ٱلْقَوْمِ ٱلْمُجْرِمِينَ ﴾

“And if they give thee the lie, say: "Limitless is your Sustainer in His grace; but His punishment shall not be averted from people who are lost in sin."”

So if they deny you with regard to what you have brought then say to them ‘Your Lord has all-embracing mercy for He does not hasten to bring about your punishment — herein is a gentle summoning of them to the faith; and His might His chastisement when it comes will never be driven back from the sinning folk’.