I would raise to put a tester bet out there, you mentioned that he folded to a shove in a hand that you observed, so it seems like he is just trying to lead out and bet a weak board. He probably had a 7 in his hand, thats all that you should give him credit for. You should definitely reraise here in order to make sure he doesn't catch another small card to increase his outs/beat your hand. If you reraise I don't see him calling with a pair of 2s.