they did not split up except after knowledge had come to them and then only because they wished to commit excesses against each other. had your lord not already decreed that judgement would be made later at an appointed time the matter between them would surely have been decided once and for all. indeed those who were later made the heirs of the book are in disquieting doubt about it.
وما تفرقوا إلا من بعد ما جاءهم العلم بغيا بينهم ولولا كلمة سبقت من ربك إلى أجل مسمى لقضي بينهم وإن الذين أورثوا الكتاب من بعدهم لفي شك منه مريب