And to free themselves from the yoke: The yoke refers to Syrian rule over the Jews. By allying themselves with Rome, Judas hoped to frighten the Syrian king Demetrius~I away from oppressing the Jews. Contemporary English Version makes this clear by rendering this clause as “in order to rescue his people from King Demetrius.”

For they saw that the kingdom of the Greeks was completely enslaving Israel: The kingdom of the Greeks refers to the Seleucid kingdom in Syria (see the comments on 1Macc 1.10). An alternative model for this clause is “for they saw that Demetrius was making all the Jews his slaves.”

We may combine verses 17 and 18 as follows:

• Judas realized [or, saw] that he needed to make an agreement [or, treaty] with the Romans in order to rescue his people from King Demetrius of Syria, who was making all the Jews his slaves. So Judas sent Eupolemus, the son of John and grandson of Accos, and Jason, the son of Eleazar, to Rome to work out an agreement of friendship with them.

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.