Tafsir of Ad-Dukhan 44:39

"We did not create them" — meaning, and what is between them — "except with the truth." This is an exclusionary exception (istithna' mufragh) from the most general circumstances; that is, we did not create them in a state of being associated with any thing whatsoever, except being associated with the truth. Therefore, the preposition and its object (al-jar wal-majrur) are in the position of a state (hal) relative to the subject. It is also permissible that they be in the position of a state relative to the object, and the particle ba denotes association in both instances.

It is also permissible that [the ba] denotes causality, and the exception is from the most general of causes; that is, we did not create them for any cause among causes, except for the cause of the truth, which is faith, obedience, resurrection, and recompense. The interpretation of association is more manifest.

"But most of them do not know."

This is an appended sentence (tadhyil) and a profound denunciation of the ignorance of those who deny the Resurrection. It is an affirmation, because their denial leads to the invalidation of all existing things: "And they consider it trivial, while it is, in the sight of Allah, grave." Because of this, the believers said: "Our Lord, You did not create this in vain; exalted are You, so protect us from the punishment of the Fire."