Deuteronomy 27:6
Thou shalt build the altar of the LORD thy God of whole stones: and thou shalt offer burnt offerings thereon unto the LORD thy God: Thou shalt build the altar of the LORD thy God of whole stones: and thou shalt offer burnt offerings thereon unto the LORD thy God:
The command is to build the altar of the Lord God of whole stones, uncut and unhewn, without shaping them with iron tools, and to offer burnt offerings upon it to the Lord. It was given as the people's response after crossing the Jordan into the promised land, with the altar to stand at Mount Ebal. It belongs to the covenant-renewal ceremony at Ebal and Gerizim, where Israel was to recognize God's law before taking possession of Canaan.
The surrounding directions required plastering stones and writing the law and commandments of God plainly upon memorial stones where all could read. They required also offering peace offerings, rejoicing before God, and having the law read aloud so the people could see the covenant terms and assent to the blessings for obedience or the curses for neglect. The verse was spoken by Jesus Christ enshrouded in the pillar of cloud with His own voice.
It belongs to the directions that express the principles of His kingdom and of the law of the kingdom of God and set out His claims on His people. They were made specific with precaution and decided practical demonstration so that minds may not be left in ignorance and uncertainty. Their exactness shows God's care over forgetful Israel and how particular He was in telling them just what to do.
Together with chapter 28 they plainly state the blessings of obedience, repeated from the two prominent positions of the mount of blessings and the mount of curses, where the advantages of the blessing and the disadvantages of the curse were pronounced. They were given to remind that obedience to God's commandments is for present and future good and brings prosperity, while disobedience results in a curse. The altar's position on the mountain where the curse was pronounced signified that by transgressing the law Israel had justly incurred God's wrath, but that the wrath would be stayed through Christ's atonement represented by the altar and its sacrifice.
It presents the never-ceasing obligation of all whom God has blessed with life and health and temporal and spiritual advantages, and whom He has specially favored, to publicly acknowledge Him so that His name will be glorified as a testimony that His Word is verity and truth. It teaches the lesson that God's commandments and warnings must be kept before the people and repeatedly taught and remembered.