Albert Barnes Commentary 1 Peter 2:6

"Because it is contained in scripture, Behold, I lay in Zion a chief corner stone, elect, precious: And he that believeth on him shall not be put to shame." — 1 Peter 2:6 (ASV)

Wherefore also it is contained in the scripture (Isaiah 28:16). The quotation is substantially as it is found in the Septuagint.

Behold, I lay in Sion. See the notes on Isaiah 28:16 and Romans 9:33.

A chief corner-stone. The principal stone on which the corner of the building rests. A stone is selected for this which is large and solid, and, usually, one which is squared and crafted with care; and as such a stone is commonly laid with solemn ceremonies, so perhaps, in allusion to this, it is said here by God that he would lay his stone at the foundation. The solemnities attending this were those which accompanied the great work of the Redeemer. See the word explained in the notes on Ephesians 2:20.

Elect. Chosen of God, or selected for this purpose (1 Peter 2:4).

And he that believeth on him shall not be confounded. He shall not be ashamed. The Hebrew is, "shall not make haste." See it explained in the notes on Romans 9:33.