And We defer it not save for a counted period.
We have appointed a specific time for it to take place.
We shall not postpone it except until a counted term
And We delay it not but for an appointed term
And We do not delay it, except a term/time counted/prepared
The Last Day (which is not too far away) will take place at its appointed time
And We do not postpone it except for a fixed term
And WE delay it not save for a computed term
And We are not deferring it but for an appointed term (which has already been fixed)
And We defer it not but for a computed term
And We delay it only for a term (already) fixed