C. F. Keil and Franz Delitzsch on 1 Kings 19:21

1Ki 19:21

Then Elisha returned, took the pair of oxen with which he had been ploughing, sacrificed, i.e., slaughtered them (זבח used figuratively), boiled the flesh with the plough, gave a farewell meal to the people (of his place of abode), i.e., his friends and acquaintance, and then followed Elijah as his servant, i.e., his assistant. The suffix in בּשּׁלם refers to הבּקר צמּד, and is more precisely defined by the apposition הבּשׂר, “namely, the flesh of the oxen.”