Deuteronomy 27:12

“And it will be, when Yahweh your God brings you into the land where you are entering to possess it, that you shall set the blessing on Mount Gerizim and the curse on Mount Ebal.

And all Israel with their elders and officers and their judges were standing on both sides of the ark before the Levitical priests who carried the ark of the covenant of Yahweh, the sojourner as well as the native. Half of them stood in front of Mount Gerizim and half of them in front of Mount Ebal, just as Moses the servant of Yahweh had given a command at first to bless the people of Israel.