Is it only then when it has come to pass when it has befallen you that you will believe therein? that is in God or it means in the chastisement when it has come down the use of hamza in a-thumma ‘is it then’ is to deny the possibility of deferrment of chastisement in other words it your belief will not be accepted from you in that instance and it will be said to you Now do you believe when until now you have been hastening it on?’ in mockery of it.