Sometimes the omitted predicate is supplied not by an earlier sentence but by the scene or the conversational question. A sudden encounter may be conveyed by naming the person alone.
«خرجت فإذا زيد»
I went out, and there was Zayd before me.
A predicate such as “present” or “there” is understood from the scene. The point is who suddenly appeared, not the explicit restatement of the fact of presence.
«إن حلا وإن مرتحلا»
Whether settled or travelling away.
In such abbreviated parallel expressions a previously understood description need not be fully repeated. Their shared condition is the listener’s ability to reconstruct the omitted element.