In Genesis Sarah’s brother, runs to meet Abraham’s servant: Laban festinus aggressus est... Why is it not festine?

In Genesis Sarah’s brother, runs to meet Abraham’s servant: Laban festinus aggressus est… Why is it not festine?

Adjective festinus is more idiomatic than adverb festine.
Latin often puts an adjective with the subject when English puts an adverb with the verb. Here Latin literally = Laban hasty runs to meet…, whereas English = Laban runs hastily to meet.