Deuteronomy 27:2-4

2And it shall be on the day when ye shall pass over the Jordan unto the land which Jehovah thy God giveth thee, that thou shalt set thee up great stones, and plaster them with plaster:

3and thou shalt write upon them all the words of this law, when thou art passed over; that thou mayest go in unto the land which Jehovah thy God giveth thee, a land flowing with milk and honey, as Jehovah, the God of thy fathers, hath promised thee.

4And it shall be, when ye are passed over the Jordan, that ye shall set up these stones, which I command you this day, in mount Ebal, and thou shalt plaster them with plaster.