Can't be anytime in Jesus life or the OT.
Matthew 16:18
And I say also unto thee, That thou art Peter, and
uponthis rock I will build my church; and the gates of hell shall not prevail against it.
will build is future. If the church was already alive Jesus would have said- I have been or will keep building my church.
I hold to Acts 2 for a simple reason:
Acts 1 King James Version (KJV)
1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
2 Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
4 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
The Apostles had not been baptized in the Holy spirit which 1 Cor. specifically declares is what is required for entrance to the body.
JOhn 20 is in the 2nd aorist so it is not needed to be an immdiate command. coupled with this passage we see it was a promised command fulfilled at Pentecost.