John Stott (2006) so beautifully and so simply summarizes the message the apostles proclaimed:
“Jesus was a man who was accredited by God through miracles and anointed by the Spirit to do good and to heal. Despite this, he was crucified through the agency of wicked men, though also by God’s purpose according to the Scriptures that the Messiah must suffer. Then God reversed the human verdict on Jesus by raising him from the dead, also according to the Scriptures, and as attested by the apostolic eyewitnesses. Next God exalted him to the place of supreme honor as Lord and Savior. He now possesses full authority both to save those who repent, believe and are baptized in his name, bestowing on them the forgiveness of sins and the gift of the Spirit, and to judge those who reject him.” (pp. 38-39)
Stott, J. (2006). The Cross of Christ (20th Anniversary edition). IVP Books.