For this is where all the people of Bethulia get their water: Revised Standard Version and Good News Translation do well to connect this clause closely with the preceding verse.

So thirst will destroy them is literally “thirst will carry them away.” Good News Translation has “when they are dying of thirst,” and Contemporary English Version “They will soon be so thirsty.”

We and our people will go up to the tops of the nearby mountains: Good News Translation‘s “Meanwhile” helps to separate the soldiers going into the mountains from those who will guard the springs (verse 12). Our people refers to their soldiers, so Good News Translation has “we and our men will go…” and Contemporary English Version “we will lead our armies….”

Camp there may be rendered “set up our tents there.”

Keep watch that not a man gets out of the city: The purpose for keeping watch is to “keep anyone from leaving the town” (Good News Translation). A subtlety may be involved with the literal man that they propose not to let out of the city. Most translations simply say something like “anyone,” which is all that is probably intended. But the Greek does specify “man” as opposed to “person,” and in fact, later in the story, they are going to allow two women to leave the besieged town.

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Judith. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here.