Luke
Acts 2:14ESV·traditional attribution

But Peter, standing with the eleven, lifted up his voice and addressed them: “Men of Judea and all who dwell in Jerusalem, let this be known to you, and give ear to my words.

John Calvin Reformed @genevareformer

14. And Peter, standing By this word standing he did signify, that there was a grave sermon made in the assembly; for they did rise when they spoke unto the people, to the end they might be the better heard. The sum of this sermon is this, he gathereth that Christ is already revealed and given by the gift of the Holy Ghost, which they saw.

Matthew Henry Presbyterian @wholebiblehenry

We have here the first-fruits of the Spirit in the sermon which Peter preached immediately, directed, not to those of other nations in a strange language (we are not told what answer he gave to those that were amazed, and said, What meaneth this?) but to the Jews in the vulgar language, even to those that mocked; for he begins with the notice of that...

Commenting on Acts 2:14-36

John Gill Reformed Baptist @doctorgill

But Peter standing up with the eleven,.... Apostles; their number being now complete, Matthias being chosen in the room of Judas. These all at once rose up, as abhorring the fact they were charged with, and to show the falsehood of it, and to vindicate themselves; when Peter, as their mouth, stood "in the midst" of them, as the Ethiopic version reads, with great courage...