Was this commission given before the separation between Jew and Gentile was eliminated?
Was this why Peter never went to Cornelius?
My understanding on that is that it was given but then interrupted (as the passage even asserts; it will continue only after His return).
It's having been interrupted was why they were so thrown when God began to deal with the Gentiles absent of Israel's Prophesied rise FIRST.
In that aspect of God's Two-Fold Purpose: Prophecy and Mystery; the Prophesied aspect - Gentiles are considered unclean as is.
Acts 11:2 And when Peter was come up to Jerusalem, they that were of the circumcision contended with him, 11:3 Saying, Thou wentest in to men uncircumcised, and didst eat with them. 11:4 But Peter rehearsed the matter from the beginning, and expounded it by order unto them, saying, 11:5 I was in the city of Joppa praying: and in a trance I saw a vision, A certain vessel descend, as it had been a great sheet, let down from heaven by four corners; and it came even to me: 11:6 Upon the which when I had fastened mine eyes, I considered, and saw fourfooted beasts of the earth, and wild beasts, and creeping things, and fowls of the air. 11:7 And I heard a voice saying unto me, Arise, Peter; slay and eat. 11:8 But I said, Not so, Lord: for nothing common or unclean hath at any time entered into my mouth. 11:9 But the voice answered me again from heaven, What God hath cleansed, that call not thou common. 11:10 And this was done three times: and all were drawn up again into heaven. 11:11 And, behold, immediately there were three men already come unto the house where I was, sent from Caesarea unto me. 11:12 And the Spirit bade me go with them, nothing doubting. Moreover these six brethren accompanied me, and we entered into the man's house: 11:13 And he shewed us how he had seen an angel in his house, which stood and said unto him, Send men to Joppa, and call for Simon, whose surname is Peter; 11:14 Who shall tell thee words, whereby thou and all thy house shall be saved. 11:15 And as I began to speak, the Holy Ghost fell on them, as on us at the beginning. 11:16 Then remembered I the word of the Lord, how that he said, John indeed baptized with water; but ye shall be baptized with the Holy Ghost. 11:17 Forasmuch then as God gave them the like gift as he did unto us, who believed on the Lord Jesus Christ; what was I, that I could withstand God? 11:18 When they heard these things, they held their peace, and glorified God, saying, Then hath God also to the Gentiles granted repentance unto life. 11:19 Now they which were scattered abroad upon the persecution that arose about Stephen travelled as far as Phenice, and Cyprus, and Antioch, preaching the word to none but unto the Jews only.
Note that last passage; which takes up where some things left off in...
Acts 8:1 And Saul was consenting unto his death. And at that time there was a great persecution against the church which was at Jerusalem; and they were all scattered abroad throughout the regions of Judaea and Samaria, except the apostles. 8:2 And devout men carried Stephen to his burial, and made great lamentation over him. 8:3 As for Saul, he made havock of the church, entering into every house, and haling men and women committed them to prison. 8:4 Therefore they that were scattered abroad went every where preaching the word.
Distinctions within those passages, for example; make it evident that any Gentiles at Pentecost were circumcised and keeping the Law of Moses.
And this is not even the tip of the iceberg on these kinds of distinctions, or things that differ in Scripture, as a governing, or guiding principle, not merely in Bible study, but in all areas of life.
Rom. 5:8
Acts 17:11,12