From time to time, God’s presence or works were such that individuals recognized particular locations as holy and treated them accordingly – they’d build an altar for sacrificial worship of God. Like the center of the Garden of Eden, these altars were the focal points of sacrificial worship with unusually potent connections to the very being of God. Sometimes altars were built in response to a covenant that God was giving the worshipper, such as in Noah case in Genesis 8 and Abraham in Genesis 12.
As Temples, these altars primarily serve as imperfect shadows of the Garden of Eden, and foreshadows of future improved forms. At that stage in history, though, it was the only recorded form of worship that reached for the presence of God, and some of these patriarchal altars remained standing (and in use!) for centuries afterwards, not only a testament to the reverence with which God’s people treated them, but also a clue that God honored these places of worship.
An interesting observation to note about these altars is that although they’re man-made, God seems to prefer them to be made of uncut stones. The point seems to be that despite the fact that humans put them together, God does not want us to think that we are able to mediate His presence ourselves. We’re called to participate in coming to Him in intentional acts of worship, but we do not have the power to do so all by ourselves. If those stone altars were carved all nicely together, the temptation to idolatry would be too great. Not that people would necessarily start worshiping the work of their hands, but that they would re-identify God according to their own terms rather than God’s terms (cf. Exodus 32:4).
Outer layer: the outside world
Middle layer: the sacrificial party
Inner layer: the one making the sacrifice