﴿ 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 that is this band of accusers not produce four witnesses to it? who had witnessed it. And since they did not produce the witnesses those in God’s sight in His judgement they are liars in this matter.