﴿ أَوَكُلَّمَا عَٰهَدُوا۟ عَهْدًۭا نَّبَذَهُۥ فَرِيقٌۭ مِّنْهُم ۚ بَلْ أَكْثَرُهُمْ لَا يُؤْمِنُونَ ﴾

“Is it not so that every time they made a promise [unto God], some of them cast it aside? Nay, indeed: most of them do not believe.”

Why whenever they make a covenant with God that they will believe in the Prophet s when he appears or that they will not give assistance to the idolaters against the Prophet s does a party of them reject it? cast it away repudiating it this is the response to the clause beginning with kullamā the interrogative of rebuke. Nay bal indicates a transition but most of them are disbelievers.