Therefore let all the house of Israel know assuredly, that God has made that same Jesus, whom you have crucified, both Lord and Christ. (Acts 2:36)
The first sermon given through the indwelling of Jesus Christ via the Spirit of God was given by Peter in Acts 2. And if you read that sermon, it is indeed all about Jesus Christ. But some like to point to what they think happened on that day as a justification for some things that are going on today – people acting drunk, etc. – but Peter quickly gathers all that was happening into a message about the Person of Christ — and what God now desires to do through Him.
Peter ended his sermon with the above verse. (Acts 2:36) It carried the conviction of the Holy Spirit. Acts records, “Now when they heard, they were pricked in their heart, and said unto Peter and to the rest of the apostles, “Men and brethren, what shall we do?” Then Peter said unto them, “Repent, and be baptized every one of you INTO the name of Jesus Christ for the remission of sins, and you shall receive the gift of the Holy Ghost.”
What was the conclusion of the events of that day? People being convicted of their lost condition and then being told to REPENT and be baptized through the spirit of God INTO Jesus Christ. That is the Greek meaning: Immersed INTO Christ (Rom. 6:35); joined to Him spiritually. (I Cor. 6:17) In other words, the outcome of the gospel message is supposed to be, yes, faith in all that Christ has DONE for us — but what He has DONE for us is all unto this end — Christ Himself NOW, IN each of us. This is what began on Pentecost in Acts 2: “Christ in YOU, the hope of glory.” (Col. 1:27)