A paragraph break is appropriate here (so Revised Standard Version).

Those who were in charge of that unlawful sacrifice took the man aside, because of their long acquaintance with him: That unlawful sacrifice means the pork was evidently from a pig that had been sacrificed on the altar. Those who were in charge of that unlawful sacrifice may refer to the Jewish priests who had made the sacrifice. They knew Eleazar personally. This first half of the verse may be rendered “The pork [or, pig meat] was part of a sacrifice, and eating it would violate the Jewish Law. The men who were supposed to make Eleazar eat it had known him a long time. They took him aside” (similarly Goldstein).

And privately urged him to bring meat of his own providing, proper for him to use: The Greek verb translated urged appears in the imperfect tense, suggesting a repeated effort to convince Eleazar to pretend compliance. His friends really did not want to see him put to death. Proper for him to use refers to meat that was allowed under God’s Law, so this clause may be rendered “that his own religion allowed him to eat.”

And pretend that he was eating the flesh of the sacrificial meal which had been commanded by the king may be expressed as “Then he could pretend that he was eating the meat from the sacrifice that the king ordered.”

Good News Bible joins verses 21-22, and it reads smoothly. Translators may use it as a model with confidence. However, possible models for verse 21 by itself are:

• The pork was part of a sacrifice, and eating it would violate the Jewish Law. The men who were supposed to make Eleazar eat it had known him a long time. They took him aside [or, They spoke to him privately] and begged him to get some meat of his own, something that was lawful to eat. Then he could pretend that he was eating the meat from the sacrifice the king had ordered.

• … They spoke to him privately, begging him, “Please get some meat of your own, something that your religion allows you to eat. Then pretend that you are eating the meat from the sacrifice that the king has ordered.”

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.