So they marched away and came with a large force into the land of Judah: Again the connector So is not necessary. The pronoun they refers to Bacchides and Alcimus, which Contemporary English Version makes clear by rendering this sentence as “Bacchides and Alcimus led a powerful army to Judea.” Good News Bible keeps the pronoun. Translators may choose the method that is good style in their language.

And he sent messengers to Judas and his brothers with peaceable but treacherous words: The writer knows that Bacchides would break his promises (see verse 16), and he lets the reader know in advance of Bacchides’ deceitfulness by describing his peaceable words as treacherous. New English Bible expresses it with “Bacchides sent envoys to Judas and his brothers to make false offers of friendship.” That is a good model. However, Good News Bible is clearer, and so is Contemporary English Version with “Then they sent Judas and his brothers some messengers who lied and promised peace.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.