Exodus 32:27

Every man his sword. Wherever the Levites saw any still persisting in the licentious rites they were to “slay” them with the sword, ignoring every tie of family and friendship (Deut. 33:8, 9; Eze. 9:6). Resolute action was necessary to quell rebellion. Jesus made it plain that no earthly ties are to be allowed to stand between us and our duty to Him (Matt. 8:21, 22; 10:37). Thus it was that the place of feasting became the place of death. This summary execution of those who led out in idolatry among the people was necessary to prove to the surrounding nations the definite displeasure of God against heathen worship. As to His own people, the Lord had to convince them that iniquity such as this would not be tolerated. Had God permitted this offense to pass without severe punishment, in the future the Jews would have the more readily yielded to the temptations of idolatry. As the loving protector of Israel, God removed from them those determined to go their own rebellious way, lest they lead others to ruin. These are times when God in His mercy permits the few to perish in order to save the many. Furthermore, if sin had persisted God could no longer have protected them and they would have fallen, defenseless, before their enemies.