The subject of throw is still “the angels” of verse 41, and the object, them, is the people who cause others to sin or who do evil. Translators should translate verses 41 and 42 together to make the sentence natural in their language.

The furnace of fire originates from Daniel 3.6. But in the apocryphal book of 2 Esdras 7.36, “the furnace of hell” is mentioned as the final place of the wicked as opposed to “the paradise of delight” where the righteous will live. Furnace of fire may be a problem if readers are not familiar with furnaces. Since, as we point out, this expression can well refer to hell, then “the fires of hell” or “into hell, which is like a great fire” are possible translations. Otherwise “the great fire” can be used.

Weep and gnash their teeth: see comments on 8.12.

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 .