John Gill Commentary Deuteronomy 27:6

"Thou shalt build the altar of Jehovah thy God of unhewn stones; and thou shalt offer burnt-offerings thereon unto Jehovah thy God:" — Deuteronomy 27:6 (ASV)

You shall build the altar of the Lord your God of whole
stones
And of such Joshua built it, (Joshua 8:31);

and you shall offer burnt offerings on it to the Lord your God;
and likely sin offerings too; for these often went together, one to make atonement for sin, and the other as a gift, and by way of thankfulness for the acceptance of the former; and both typical of Christ, the true sacrifice, and the antitype of all the legal sacrifices.