A.T. Robertson Commentary Mark 12:17

"And Jesus said unto them, Render unto Caesar the things that are Caesar`s, and unto God the things that are God`s. And they marvelled greatly at him." — Mark 12:17 (ASV)

Marvelled greatly at him (εξεθαυμαζον επ' αυτω). Imperfect tense with perfective use of the preposition εξ. Both Matthew and Luke use the ingressive aorist. Luke adds that they "held their peace" (εσιγησαν) while Matthew notes that they "went their way" (απηλθαν), went off or away.