Adam Clarke on Matthew 18:34

Delivered him to the tormentors - Not only continued captivity is here intended, but the tortures to be endured in it. If a person was suspected of fraud, as there was reason for in such a case as that mentioned here, he was put to very cruel tortures among the Asiatics, to induce him to confess. In the punishments of China, a great variety of these appear; and probably there is an allusion to such torments in this place. Before, he and all that he had, were only to be sold. Now, as he has increased his debt, so he has increased his punishment; he is delivered to the tormentors, to the horrors of a guilty conscience, and to a fearful looking for of fiery indignation, which shall devour the adversaries. But if this refers to the day of judgment, then the worm that dieth not, and the fire that is not quenched, are the tormentors.