Deuteronomy 11:29
And it shall come to pass, when the LORD thy God hath brought thee in unto the land whither thou goest to possess it, that thou shalt put the blessing upon mount Gerizim, and the curse upon mount Ebal. And it shall come to pass, when the LORD thy God hath brought thee in unto the land whither thou goest to possess it, that thou shalt put the blessing upon mount Gerizim, and the curse upon mount Ebal.
This instruction belongs to Moses' rehearsal to Israel before the people entered Canaan. It expresses God's will and His requirements for Israel by setting a blessing and a curse before them. The blessing is for obeying the commandments of the Lord, and the curse is for refusing to obey and turning aside out of the way to go after other gods. These requirements were to be framed into song and sung in the congregations of Israel so they would not forget them.
The setting forth of blessing and curse was to take place when God had brought the people into the land to possess it, after entering the promised land. The ceremony took place in the vale of Shechem, with the blessing proclaimed from the prominent Mount Gerizim, hence known as the Mount of Blessing, and the curse from Mount Ebal. From those two mountains were presented the advantages of blessing and the disadvantages of the curse, so that the consequences of obedience and disobedience were made clear. The command called the tribes to gather at Shechem to publicly recognize God's law and renew their covenant loyalty before taking possession of their inheritance.
This religious duty was to be put before further military operations, and the people could travel through enemy territory safely while faithful to God. The word was verified when Israel disobeyed, so that only two of the adults who left Egypt entered Canaan while the rest died in the wilderness. Israel fell short of the ideal set before them. The eighth and eleventh chapters of Deuteronomy mean much today and their lessons are of the greatest importance, given as truly to present believers as to Israel, so that God sets before His people this day a blessing and a curse. The Lord will vindicate His word today if leaders of His people depart from His commandments.