لَولا جاءوا عَلَيهِ بِأَربَعَةِ شُهَداءَ ۚ فَإِذ لَم يَأتوا بِالشُّهَداءِ فَأُولـٰئِكَ عِندَ اللَّهِ هُمُ الكاذِبونَ

Why didn’t they produce four witnesses for it? If they don’t produce the witnesses, then in the sight of God, they are the liars.