Peter instructed:
"Repent and let everyone of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit. For the promise is to you, and to your children, and to all who are afar off, as many as the Lord our God will call. And with many other words he testified and exhorted them saying 'Be saved from this perverse generation." Acts 2:38-40
Doesn't read to me like Peter was still in the dark to Truth, or that Peter was keeping any secrets. In fact, just the opposite. Peter was opening up the prophecy of Joel to the understanding of his listeners.
Peter proclaimed the Gospel of Jesus Christ . . . not a "murder indictment." That is a poor excuse to deny that Peter was filled with the Holy Spirit and the Truth of God.
Acts 2:22 Ye men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as ye yourselves also know:
Acts 2:23 Him, being delivered by the determinate counsel and foreknowledge of God, ye have taken, and by wicked hands have crucified and slain:
Acts 2:24 Whom God hath raised up, having loosed the pains of death: because it was not possible that he should be holden of it.
...
Acts 3:12 And when Peter saw it, he answered unto the people, Ye men of Israel, why marvel ye at this? or why look ye so earnestly on us, as though by our own power or holiness we had made this man to walk?
Acts 3:13 The God of Abraham, and of Isaac, and of Jacob, the God of our fathers, hath glorified his Son Jesus; whom ye delivered up, and denied him in the presence of Pilate, when he was determined to let him go.
Acts 3:14 But ye denied the Holy One and the Just, and desired a murderer to be granted unto you;
Acts 3:15 And killed the Prince of life, whom God hath raised from the dead; whereof we are witnesses.
A murder indictment and their reaction was:
Acts 2:37 Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?
Peter did not preach "that Christ died for our sins"! That is not Peter glorying in the cross!
Peter didn't know Paul's gospel until Paul went up by revelation and communicated it unto them (Galatians 2).
God had the wisdom and the power to keep Paul's my gospel a mystery until He wanted it revealed! It is wisdom that you deny!