﴿ لَّوْلَا جَآءُو عَلَيْهِ بِأَرْبَعَةِ شُهَدَآءَ ۚ فَإِذْ لَمْ يَأْتُوا۟ بِٱلشُّهَدَآءِ فَأُو۟لَٰٓئِكَ عِندَ ٱللَّهِ هُمُ ٱلْكَٰذِبُونَ ﴾

“why do they not [demand of the accusers that they] their allegation? for, if they do not produce such wit­nesses, it is those [accusers] who, in the sight of God, are liars indeed!”

(Why did they not produce four witnesses) four, upright witnesses to support their claim? (Since they produce not witnesses) four witnesses, (they verily are liars in the sight of Allah).