Scripture uses the word “Christ” to refer to multiple subject, depending upon the context. Since it means “an anointed one” it is used of men who are anointed by God and also of the Messiah. After the resurrection of Jesus, the term “Christ” is given another definition. Prior to His resurrection He came to the Jewish people as their Messiah. After the resurrection the title is describing His resurrected and glorified state.
Therefore, let all the house of Israel securely experientially know that God has made Him both Lord and Christ, this Jesus Whom you crucified, Acts 2:36
Since He is already referred to as Lord and Christ prior to His resurrection, having been made Lord and Christ after His resurrection adds new meaning to the words, which is understood by the context. He is now the risen and glorified One – Christ.
The Christ is also used of a new creation that God made after the resurrection of Jesus in which Jesus is the head and the Church is His body.
Therefore, since someone is in Christ; a new creation, archaic things have passed away, behold all things have become new, 1 Corinthians 5:17
We do not become a new creature, it is the Christ that is a new creation! The issue in many of our English translations is the addition of “he is” and the miss translation of the word creation to creature. In other passages of Scripture these same translations correctly define the word; however, error has been allowed to stand in this passage by adding and modifying words so it does not reflect the original statement. The Christ is a new creation, we are not a new creature.
And put all under His feet, and gave Him to be [the] head concerning all the Church, which is His body, the fullness of the One filling the all things in all ways, Ephesians 1:22. 23