God instructed Israel to leave Mount Sinai, but He would not accompany them.
Through the intercession of Moses, GOD turned away from destroying the Israelites for their idolatry with the golden calf. GOD told Moses it was time for Israel to leave Mount Sinai, but there was a big consequence for the journey as a result of Israel’s sin:
1 Now the Lord said to Moses, “Depart, go up from here, you and the people you brought out of the land of Egypt, to the land I swore to Abraham, Isaac, and Jacob, saying, ‘To your seed I will give it.’ 2 I will send My Angel before your face, and I will drive out the Amorite, the Hittite, the Perizzite, the Gergesite, the Hivite, the Jebusite, and the Canaanite. 3 I will bring you into a land flowing with milk and honey; for I will not go up in your midst, lest I consume you on the way, for you are a stiff-necked people.” 4 When the people heard this bad news, they mourned in lamentations. 5 For the Lord said to the children of Israel, “You are a stiff-necked people. Beware, lest I inflict another plague on you and consume you. Now therefore, take off your bright clothes and ornaments, and I will show you what I will do.” 6 So the children of Israel stripped themselves of their bright clothes and ornaments by Mount Horeb.
(Exodus 33:1-6 OSB)
GOD promised to send His Angel with Israel into the land, but He would not accompany them any longer lest He destroy them for their rebelliousness.
This was GOD’s way of communicating to the ancient Israelites that their wickedness introduced separation with GOD and would not be tolerated.