God's command to Moses to take vengeance on the Midianites is a response to the earlier incident where the Midianites, through the counsel of Balaam, led the Israelites into sin by enticing them into idolatry and immorality. This was a significant breach of the covenant relationship between God and His people, resulting in a plague that had devastating effects on the Israelites. The call for vengeance is not about personal revenge but rather an act of divine justice, aiming to correct the wrongs and restore holiness among the people of Israel.
The instruction also signifies the nearing end of Moses' leadership. "After that, you will be gathered to your people" indicates that Moses' mission is almost complete. This phrase reflects the biblical understanding of death as being gathered to one's ancestors, suggesting a peaceful transition after fulfilling one's divine purpose. The passage underscores the themes of justice, divine retribution, and the completion of a God-given mission, reminding believers of the importance of faithfulness and obedience to God's commands.