A useful diagnostic asks three questions: Is a specific object intended? Is it verbally present? What does the speaker want the listener to notice?
ConstructionTypical rhetorical purpose
No implied objectCharacterize the agent by an action in general
Specific object omittedRely on a cue, achieve economy or preserve decorum
Object expressly mentionedIdentify the participant, remove ambiguity, complete the point
Object or complement preposedMark focus, restriction or corrective contrast
The essential contrast is between the objectless “yaʿlamūn,” the understood pronoun in “mā qalā,” and the expressed, fronted object in “iyyāka naʿbudu.” The next level develops restriction (القصر) as a separate subject.