But he was a prophet and knew that God had promised him on oath that He would place one of his descendants on his throne.
30. Therefore, seeing he was a prophet He showeth, by two reasons, that it is no marvel if David do speak of things that should come to pass long after his time; the former is, because he was a prophet. And we know that things to come, and such as are removed far from the knowledge of men, are revealed unto the prophets.
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
Therefore being a prophet,.... Who could foretell things to come, as he did many things concerning the sufferings and death of Christ, and the circumstances attending it, concerning his resurrection, ascension, and session at the right hand of God. So the title of his "Psalms", in the Syriac version, runs thus; the "Book of the Psalms of David, King and Prophet": and in the Arabic...