Earthen Altars!
The Message words it, "Earthen Altars". That is what God has called us to be. He won't stand for anything else that we would put up in front of or even next to him, i.e. anything of this world. He simply wants us to be the altar in which we offer up the things that are important to us. Not dressed up or dressed out, nothing fancy or showey; Just us! Anywhere and everywhere, at anytime, are we supposed to offer ourselves to God almighty.