After the feast called Pentecost: Good News Bible handles this phrase well, inserting the information that Pentecost is the Greek name for “Harvest Festival” (Revised Standard Version “feast of weeks”) in verse 31. Translators may use the same name in both verses. If they do this, we suggest using the name in verse 31.

They hastened against Gorgias, the governor of Idumea: For Gorgias see 2Macc 8.9 and 10.14; for Idumea see 1Macc 3.41. This clause may be translated “Judas and his soldiers quickly left Jerusalem and attacked Gorgias, the governor of Idumea.”

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.