What message did Stephen proclaim to Israel before he was stoned?
Stephen appealed to the nation of Israel to realize and believe that the One they had killed was indeed the Messiah, the Christ, the Son of the living God. His message centered on their need to acknowledge that Messiah, yet they stoned him.
Les explains that Acts is a transitional book. After the crucifixion and resurrection, Peter and the eleven were still appealing to Israel to repent of killing their Messiah, and God would yet pick up where He left off and send the king, so they could have the kingdom. Stephen likewise appealed to the nation of Israel to realize and believe that the One they had killed was indeed the Messiah, the Christ, the Son of the living God. But instead they stoned him, and at the feet of Saul of Tarsus they laid their cloak. This introduces Saul of Tarsus, a Jew and Pharisee of the Pharisees, who hated the name of Jesus of Nazareth because of his religious convictions and thought he was doing God's service by stamping out early Jewish believers that Christ was the Messiah.