فَبِأَىِّ حَدِيثٍۭ بَعْدَهُۥ يُؤْمِنُونَ Qur’an Al-Mursalat (77:50)Fabiayyi h adeethin baAAdahu yuminoon a
"That" may refer to verse 48: they were given plain and clear Guidance, and they refused to accept it: after that what kind of Message will they accept? The Guidance referred to is obviously that of Islam or the Qur-an.