Alright, let's see here, are you aware that God was originally going to use Israel to reach the world? But then when Paul (then known as Saul) started persecuting the Jews, leading up to his conversion, God cut off Israel and grafted in the Gentiles?
Are you aware that Jesus fully intended to return quickly after his ascension? but then because of His people rejecting Him, He put His plans for Israel on the backburner, so to speak, and switched to plan B, which was to save the Gentiles first, then eventually return to His people, Israel?
Now, I'm not saying that Peter and the rest of the Apostles preached Christ's DBR. Because they didn't. However, Jesus Himself told them that He would die, be crucified, and then be raised from the dead, and throughout His ministry too, he hinted at it. What I'm saying is that they didn't understand Him, as they thought He was there to establish His Kingdom, not be Crucified.
I think it needs to be said so that everyone is reminded that the Apostles didn't really teach very much at all prior to Christ's DBR, they mostly lived as students under a teacher.