He could not pay can be expressed as “he did not have the money to pay the debt” or “he was unable to repay.” It may be necessary to add an indirect object, as “repay his master” or “pay the king the money he owed him.”

His lord in this context means “his master” or “the king.”

Ordered him to be sold is represented in Good News Translation as “ordered him to be sold as a slave,” which makes the meaning immediately obvious for the reader. The man and everything he owned were to be sold as compensation for the debt. This action is purely for the sake of revenge on the part of the king, since even at the highest value of slaves the total amount would have still been insignificant as compared with the monstrous debt of verse 24.

This last part of the verse may need to be restructured, as in “his master ordered that the man and his wife and children be sold as slaves and that everything he owned also be sold in order to pay the debt” or “the king ordered his people to take the man and his wife and children and sell them as slaves, and also to sell the man’s possessions. This money would be used to pay off the debt.”

The severity of the punishment is thereby in keeping with the enormity of the debt. According to the Jewish Law, a man could not be sold except in the case of theft. And the sale of a man’s wife was strictly forbidden. So Jesus draws upon an illustration from a non-Jewish setting to underscore the severity of the punishment. Both the magnitude of the debt and the enormity of the punishment are intended to stagger the imagination.

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .