Jeremiah 33:19-21 ” The Word of the Lord came to Jeremiah: This is what the Lord says: If you can break My covenant with the day and My covenant with the night, so that day and night no longer come at their appointed time, then My covenant with David My servant – and My covenant with the Levites who are priests ministering before Me – can be broken…”

Just as Psalm 72:5 used the images of the sun & the moon as symbols of longevity…so here the Lord is comparing the security of His promises to restore Israel and His Kingdom with the constancy of day following night. It shows His commitment as unchanging as the course of the day…from His Davidic Covenant in II Samuel 7:12-16 to His covenant with the Tribe of Levi in Numbers 1:47-54…God assures them and us that nothing will ever make null & void His everlasting promises for His people.