What is a cornerstone?

The beauty of the examples and analogies Jesus uses is that any person can intuitively understand them, even if they are not familiar with them. Even if we're not farmers, we understand 'we are the sheep and He is the Shepherd.' Even if we're not gardeners, we understand when He says He is the vine and we are the branches.' Even though we might not be a builder, we understand when it's written that He is the chief cornerstone.

But it brings more depth and understanding to bear when we delve more deeply into some of these analogies. So let's look at Cornerstone.

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The stone that the builders rejected has become the cornerstone (Psalm 118:22).

therefore thus says the Lord GOD, "Behold, I am the one who has laid as a foundation in Zion, a stone, a tested stone, a precious cornerstone, of a sure foundation" (Isaiah 28:16).

let it be known to all of you and to all the people of Israel that by the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead—by him this man is standing before you well. 11 This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone. (Acts 4:10–11).

So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, 20 built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone (Ephesians 2:19–20).

As you come to him, a living stone rejected by men but in the sight of God chosen and precious, you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ. For it stands in Scripture:
"Behold, I am laying in Zion a stone, a cornerstone chosen and precious," (1 Peter 2:4–6).

A cornerstone in the House of Giove and Ganymede

Did you know that the concept of cornerstone was mentioned these several  times in scripture? We can understand that cornerstone is important to a building. But how important? What does a cornerstone do? What is its function? What would happen if the cornerstone was removed?

A stone that can be in the foundation, above ground level or at the summit of the roof (the "capstone"). The cornerstone of a large building gives it a reliable and firm foundation, leading to the cohesion and stability of the whole building. In Scripture, such foundation-stones are taken as symbolic of the basis of faith in Jesus Christ and the church. Jesus Christ is thus represented as both the foundation upon which the church is built, and the capstone which crowns the whole. Manser, M. H. (2009). Dictionary of Bible Themes

Also-

The most significant stone in important buildings is the cornerstone. Usually it is the first stone laid at a formal ceremony. Often it is engraved with the date of the building and perhaps some other ascription, honoring a person or an event. Thus, it should come as no surprise that Jesus is called the gōnia or "cornerstone" of the church. In fact, Jesus used this title for Himself. Carpenter, E. E., & Comfort, P. W. (2000). In Holman treasury of key Bible words

I thought this architectural description from Wikipedia was the clearest:

The cornerstone (or foundation stone) concept is derived from the first stone set in the construction of a masonry foundation, important since all other stones will be set in reference to this stone, thus determining the position of the entire structure.

Is Jesus your cornerstone? Does He determine the position of your entire life?


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Further Reading

Making Christ Attractive in a Pagan World
JMac July 2 2017 sermon segment on the cornerstone