Pillars of Memorial: To Commemorate Remarkable Events
Source: TTT
Exodus 24:4
And Moses wrote down all the words of the LORD. Early the next morning he got up and built an altar at the base of the mountain, along with twelve pillars for the twelve tribes of Israel.
Joshua 4:20, 24
And there at Gilgal Joshua set up the twelve stones they had taken from the Jordan. / He did this so that all the peoples of the earth may know that the hand of the LORD is mighty, and so that you may always fear the LORD your God.”