How long after Pentecost did Peter and the apostles offer the king to Israel?
Peter and the apostles offered Jesus as Israel's king for about seven years after Pentecost, though the context allows at least six years or better. They continued presenting Him as their risen King even though Israel had crucified Him, because God had raised Him from the dead and He could still be their king.
Les explains that Acts chapter 7 is Stephen's sermon, and that Peter and the eleven had been doing this for the last several years—about seven years after Pentecost, or at least six or better. He notes that for that period Peter, the eleven, and other believing Jews kept presenting Israel with their king, even though they had crucified Him. Since God raised Him from the dead, He could still be their king. Stephen then begins his own appeal to the nation, trying to convince them that the one they killed was their Messiah.