This theme of the stumbling stone is a bit cryptic, but it’s one of the favorite motifs of all the Biblical authors.
Paul uses it here, and it is seen in the writings of Moses, David, Solomon, Isaiah, all the gospel writers, and multiple times in Paul, and Peter uses it as well.
Paul’s exact quotation here seems to be a conflated quote from Isaiah 8, and Isaiah 28, with a veiled allusion to Psalm 118 as well.
Isaiah 8:14–15 NASB95
“Then He shall become a sanctuary;But to both the houses of Israel, a stone to strike and a rock to stumble over,And a snare and a trap for the inhabitants of Jerusalem.“Many will stumble over them,Then they will fall and be broken;They will even be snared and caught.”
Isaiah 28:16 NASB95
Therefore thus says the Lord God,“Behold, I am laying in Zion a stone, a tested stone,A costly cornerstone for the foundation, firmly placed.He who believes in it will not be disturbed.
Psalm 118:22 NASB95
The stone which the builders rejectedHas become the chief corner stone.