Aretas - (Easton's Bible Dictionary)
The father-in-law of Herod Antipas, and king of Arabia Petraea. His daughter returned to him on the occasion of her husband's entering into an adulterous alliance with Herodias, the wife of Herod-Philip, his half-brother (Luke 3:19, 20; Mark 6:17; Matt. 14:3). This led to a war between Aretas and Herod Antipas. Herod's army was wholly destroyed (A.D. 36). Aretas, taking advantage of the complications of the times on account of the death of the Emperor Tiberius (A.D. 37), took possession of Damascus (2 Cor. 11:32; comp. Acts 9:25). At this time Paul returned to Damascus from Arabia.