Albert Barnes on Matthew 21:41

They say, etc. They answered according as they knew men would, act and would act justly in doing it. He would take away their privileges, and confer them on others. This was the answer which Jesus wished. It was so clear, that they could not answer otherwise. He wished to show them the justice of taking away their national privileges, and punishing them in the destruction of their city and nation. Had he stated this at first, they would not have heard him. He, however, by a parable led them along to state themselves the very truth which he wished to communicate, and they had then nothing to answer, they did not, however, yet see the bearing of what they had admitted.

(a) "destroy" Ps 2:4,5,9, Zech 12:2 (b) "other husbandmen" Lk 21:24, Rom 9:26, 11:11