Revised Standard Version expresses this verse literally. The unusual word order of the Greek sentence is probably a characteristic of a formal legal document. If translators are working in a culture that has a readily recognized formal style for such pronouncements, they may consider using it here. Otherwise they should use natural word order, as Good News Bible has done in English.

To the nation of the Jews, who are our friends and fulfil their obligations to us: Fulfil their obligations to us may be translated “have kept all their agreements with us.” Good News Bible says “keep their treaty obligations,” which is also possible.

We have determined to do good may be rendered “we have decided to show them much favor” or “… treat them very well.”

Because of the good will they show toward us repeats the idea in who are our friends and fulfil their obligations to us. This repetition is also a mark of formal legal language. Good News Bible combines the two clauses, saying “because they are our loyal allies and keep their treaty obligations.”

An alternative model for this verse is:

• The Jews are our friends, and I have decided to treat them with much favor [or, be very good to them], since they are our allies [or, they are very loyal to us] and I can trust them to keep their promises [or, fulfill their treaty obligations].

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.