Charles Spurgeon Commentary Matthew 18:30

"And he would not: but went and cast him into prison, till he should pay that which was due." — Matthew 18:30 (ASV)

Not that he could not, but that he would not. He gave no time, proposed no settlement, promised no mercy. He used the law of his own generous king as a means of treading down his poor fellow servant.

He personally attended to the debtor’s arrest. He went and cast him into prison. He sees him sentenced to a debtor’s dungeon, with no hope of coming out again unless by payment.

It was his lord’s own prison, too. He was making use of his generous sovereign’s lock-up to gratify his own malevolence. He vowed that his fellow servant would lie there until he paid the debt.

Base conduct this! As common as it is base!