“For it stands in Scripture: ‘Behold, I am laying in Zion a stone, a cornerstone chosen and precious, and whoever believes in him will not be put to shame.’ So the honor is for you who believe, but for those who do not believe, ‘The stone that the builders rejected has become the cornerstone,’ and ‘A stone of stumbling, and a rock of offense’…” (1 Peter 2:6-8 ESV).
In addition to its use as a stone that joins two walls together, a cornerstone may also serve as the foundation stone of a building project. The following commentators explain the function of a cornerstone in this regard…
“A cornerstone is the visible support on which the rest of the building relies for strength and stability. Believers trust in Christ much as a building rests on its cornerstone.” (1)
The ‘corner stone’ refers to the main stone on which the building rests. It does not refer to a modern ‘cornerstone,’ or to the last stone the mason put at the top of the building, the ‘keystone’ (Isa. 28:16; cf. Eph. 2:20). In view of this, it seems that the rock (Gr. petra, a large stone), to which Jesus referred in Matthew 16:18, was not Peter (Gr. Petros, a small stone), but Himself. Jesus, not Peter, much less Judaism, is the Foundation upon which God has promised to build the church (cf. 1 Cor. 3:11).” (2)
Construction workers in the Biblical era also made use of a cornerstone as an alignment tool to position other stones in a building structure. Today, a 21st century building contractor has an array of electronic tools to ensure that a new building project adheres to an architect’s specification or local building code. But in Peter’s day, a carefully hewn cornerstone was used to measure and adjust the dimensional aspects of a building during the construction process.
That function leads to an easy application from our text here in 1 Peter 2:6-8. Just as the fixed point of an ancient cornerstone served to align the parameters of a newly constructed building, Jesus serves a similar role in our lives. As we prayerfully look to Jesus’ example in the Scriptures, we find the right standard for the choices and decisions we have to make over the course of our daily lives.
It is in this manner that we can “…set an example for the believers in speech, in conduct, in love, in faith, and in purity” (1 Timothy 4:12 CSB).
(1) John F. Walvoord and Roy B. Zuck, Bible Knowledge Commentary, note on 1 Peter 2:6 pg. 845
(2) Constable, Thomas. DD, Notes on 1 Peter 2023 Edition “3. Building on Christ 2:6-8” [2:6] https://www.planobiblechapel.org/tcon/notes/html/nt/1peter/1peter.htm