"And had Allah not decreed for them the exile, He would have punished them," meaning: had Allah not ordained for them the exile to al-Sham, He would have punished them in this world with killing and captivity.
Muhammad said: It is said 'jala'u' (they departed/exiled) from their land, and 'ajlaytuhum' (I exiled them), and 'jalawtuhum' as well.
﴿وَلَوْلا أَنْ كَتَبَ اللَّهُ عَلَيْهِمُ الْجلاء لعذبهم﴾ لَوْلَا أنّ اللَّه حكم عَلَيْهِم بالجلاء إِلَى الشَّام لعذّبهم فِي الدُّنْيَا بِالْقَتْلِ والسَّبْي.
قَالَ محمدٌ: يُقَال جَلَوْا من أرضهمْ وأجْلَيْتُهم وجَلَوتُهم أَيْضا.