Passage
*He* is the stone which has been set at nought by you the builders, which is become the corner stone.
*He* is the stone which has been set at nought by you the builders, which is become the corner stone.
Acts 4:9 if *we* this day are called upon to answer as to the good deed [done] to the infirm man, how *he* has been healed,
Acts 4:10 be it known to you all, and to all the people of Israel, that in the name of Jesus Christ the Nazaraean, whom *ye* have crucified, whom God has raised from among [the] dead, by *him* this [man] stands here before you sound [in body].
Acts 4:11 *He* is the stone which has been set at nought by you the builders, which is become the corner stone.
Acts 4:12 And salvation is in none other, for neither is there another name under heaven which is given among men by which we must be saved.
Acts 4:13 But seeing the boldness of Peter and John, and perceiving that they were unlettered and uninstructed men, they wondered; and they recognised them that they were with Jesus.
The verse centers on "stone", "been", "nought", "builders", "become", and "corner". It is saying that the verse draws attention to "stone" and "been", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 10's "be it known to you all and..." into verse 12's "And salvation is in none other for...", so "stone" and "been" belong inside that flow. In Acts context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "stone" and "been" with trust shaped by these words, not by a vague optimism outside the passage.