Rashi on Exodus 10:8/רש"י על שמות י׳:ח׳

1ויושב [AND MOSES AND AARON] WERE BROUGHT BACK (The verb has a passive meaning [Hophal], not an active as the particle את before משה and אהרן might lead one to suppose) — They were brought back by a messenger: they (Pharaoh’s servants) sent people after them and these brought them back to Pharaoh.