In Numbers 16:21, Moses warns the rebellious group led by Korah, Dathan, and Abiram of the severe consequences of their actions. He declares that if these men die a natural death, it would indicate that God did not send him, but if the earth swallows them up, it would confirm that they have treated the Lord with contempt. This verse showcases the authority and divine backing of Moses' leadership, as well as the gravity of challenging God's chosen representatives. It serves as a sobering reminder of the importance of respecting God's appointed leaders and following His commands to avoid facing His righteous judgment.