Elsewhere in the New Testament the adjective worthless is found only in Luke 17.10. Good News Translation‘s “As for this useless servant—throw him…” represents an attempt to express the position of emphasis which the worthless servant occupies in the Greek sentence. It may be better to use a complete sentence: “But this servant is worthless! Take him and throw him….”

Outer darkness was discussed at 8.12.

There men will weep and gnash their teeth has no subject in Greek. Good News Translation supplies a different subject: “there he will cry and gnash his teeth.” Die Bibel im heutigen Deutsch retains the impersonal structure: “Throw this good-for-nothing out in the darkness, where there is nothing except crying and gnashing of teeth.” Matthew employs this formula six times (see comment at 8.12); outside his Gospel it is used only in Luke 13.28.

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 .