رَجَعَ الرَّسُولُ وَهُوَ يَحْمِلُ الرِّسَالَةَ.
The messenger returned while carrying the message.
Rajaʿa is the verb and al-rasūlu its subject. Wa-huwa yaḥmilu al-risāla is a nominal circumstantial sentence: huwa is its subject, and the verbal clause is its predicate. Both the circumstantial wāw and the pronoun link the state to the messenger at the time of returning.
In rajaʿa al-rasūlu wa-ḥamala al-risāla, the second finite verb can instead be coordinated as another action. Interpretation depends on clause structure and the intended temporal relation, not the mere presence of wāw.