قُلْ هُوَ اللَّهُ أَحَدٌ.
Meaning: Say: the matter is that Allah is One.
Source-aligned parsing: qul is an imperative with concealed anta; huwa is the pronoun of affair, serving as initial subject; Allāhu is a second subject; aḥadun is its predicate; the clause “Allāhu aḥadun” is the predicate of huwa; the entire quoted clause is the object of qul.
Here huwa introduces the proposition rather than referring to an ordinary male antecedent.