The translation goal includes approximating the Arabic in the number and alignment of words. Close alignment helps a reader see which translated expression corresponds to a word or construction in the source and where explanation has been added.
Yet Arabic and Persian cannot always be matched term for term. One Arabic verb may require several words in another language, while a strictly literal rendering of a construction may obscure the intended relationship.
Balance: formal closeness is valuable as a teaching aid, but it should not be pursued so rigidly that the translated meaning becomes obscure or incorrect.