The Gospel According to The Apostles.

Peter
Acts 2:23-24
23This man was handed over to you by God's set purpose and foreknowledge; and you, with the help of wicked men, put him to death by nailing him to the cross. 24But God raised him from the dead, freeing him from the agony of death, because it was impossible for death to keep its hold on him.

Acts 3:13-15
13The God of Abraham, Isaac and Jacob, the God of our fathers, has glorified his servant Jesus. You handed him over to be killed, and you disowned him before Pilate, though he had decided to let him go. 14You disowned the Holy and Righteous One and asked that a murderer be released to you. 15You killed the author of life, but God raised him from the dead. We are witnesses of this.

Acts 4:10
10then know this, you and all the people of Israel: It is by the name of Jesus Christ of Nazareth, whom you crucified but whom God raised from the dead, that this man stands before you healed.

Acts 10:39-40
39"We are witnesses of everything he did in the country of the Jews and in Jerusalem. They killed him by hanging him on a tree, 40but God raised him from the dead on the third day and caused him to be seen.

Peter and Others
Acts 5:29-31
29Peter and the other apostles replied: "We must obey God rather than men! 30The God of our fathers raised Jesus from the dead—whom you had killed by hanging him on a tree. 31God exalted him to his own right hand as Prince and Savior that he might give repentance and forgiveness of sins to Israel.

Acts 5:42
42Day after day, in the temple courts and from house to house, they never stopped teaching and proclaiming the good news that Jesus is the Christ.[a]

Stephen
Acts 7:52
52Was there ever a prophet your fathers did not persecute? They even killed those who predicted the coming of the Righteous One. And now you have betrayed and murdered him—

Acts 7:55-56
55But Stephen, full of the Holy Spirit, looked up to heaven and saw the glory of God, and Jesus standing at the right hand of God. 56"Look," he said, "I see heaven open and the Son of Man standing at the right hand of God."

Paul
Acts 9:20
Saul spent several days with the disciples in Damascus. 20At once he began to preach in the synagogues that Jesus is the Son of God.

Acts 13:28-30
28Though they found no proper ground for a death sentence, they asked Pilate to have him executed. 29When they had carried out all that was written about him, they took him down from the tree and laid him in a tomb. 30But God raised him from the dead,

Acts 17:30-31
30In the past God overlooked such ignorance, but now he commands all people everywhere to repent. 31For he has set a day when he will judge the world with justice by the man he has appointed. He has given proof of this to all men by raising him from the dead."

Acts 18:28
28For he vigorously refuted the Jews in public debate, proving from the Scriptures that Jesus was the Christ.

Acts 26:8
8Why should any of you consider it incredible that God raises the dead?

Acts 26:23
23that the Christ would suffer and, as the first to rise from the dead, would proclaim light to his own people and to the Gentiles."

The gospel the Apostles preached was that Jesus is the Christ, the Son of God and he is Lord: He suffered under Pontius Pilate, was crucified, died, and was buried.
On the third day He arose again from the dead.
He ascended into heaven and sits at the right hand of the Father and he shall come to judge the living and the dead.

This is the gospel I believe