The altars that Abraham built in Genesis 12 were located in the region that God promised to his
ancestors descendants. In a sense they were like little flags planted by an exploration party, claiming the land in the name of a country that was still on its way. Eventually the entire land of Canaan was to belong to God’s people, Israel, and although there were altars in it, and more on the way, there is a sense in which the entire land was a sort of Temple. In Exodus 15, Moses records a victory song after the Egyptians were drowned in the Red Sea, saving Israel from slavery and freeing them to travel up to the Promised Land. In verses 17-18 he wrote “You will bring them in and plant them on your own mountain, the place, O LORD, which you have made for your abode, the sanctuary, O Lord, which your hands have established. The LORD will reign forever and ever.” This is Temple language. Altars were often built on hilltops, the sanctuary is the very center of a Temple building, and the image of God reigning suggests that His throne (and therefore His house) will be there among them.
Of course, having a country which was made entirely of holy ground came with a price – only those who are worshiping God belong in his Temple. Failure to do so profanes the holy place, and the more holy the place (or the more present God is), the worse the punishment, as we shall see with the Ark of the Covenant. The prophet Joel warned of such a coming punishment for Israel’s sin in the holy land, and in 2:3 he declared “The land is like the garden of Eden before them, but behind them a desolate wilderness.” The Temple-like nature of the Garden of Eden, then, clearly transfers over to the Promised Land. Of course, the profundity of God’s presence in Canaan is nothing compared to the Garden, but it’s a huge step up from just seeking Him at altars scattered about the countryside.
Outer layer: the outside world
Middle layer: the land of Canaan
Inner layer: a shrine, or an altar, or Jerusalem