What is a chief cornerstone in ancient architecture?
In ancient architecture, especially arches, the chief cornerstone is the final stone placed at the center of the top of the arch. All the rest of the arch rests against that one, so it becomes the chief stone that holds the structure together.
Les explains that in ancient architecture, especially arches, the final stone placed at the center of the top of the arch is the chief stone, and all the rest of the arch rests against it. He shares a legend, not Scripture, about Solomon's temple: every stone was perfectly pre-cut at the quarries so there was never a hammer sound at the site. The chief cornerstone came to the builders, but in their confusion they could not find a place for it, so they dragged it to a vacant lot where weeds grew around it, and people taking shortcuts stumbled over it. Les says this legend is apropos because Peter uses it as an analogy: Israel was the builder of God's Kingdom, and their Christ was to be the Messiah, the chief corner stone that would hold it all together. But Israel rejected it and threw it out, so Christ became to the nation of Israel a stone of stumbling.