Luke 24:49
And look, I [am going to] send upon you apostles what my Father promised [i.e., the Holy Spirit. See John 14:26]; but you should wait in the city [of Jerusalem] until you are clothed with power from above." [Note: This promise was fulfilled when the apostles were immersed in the Holy Spirit. See Acts 1:4 - 2:4].
Acts 1:4
[One day, as He was] gathered with these apostles, He urged them not to leave Jerusalem, but to wait there until they received what the Father had promised them. (Jesus had previously discussed this with them). [See Luke 24:49].
John 14:26
But the Helper, that is, the Holy Spirit, whom the Father will send in my name [i.e., by my authority] will teach you everything. And He will remind you of everything that I [have] said to you.
Acts 1:8
But, you apostles will receive power when the Holy Spirit descends on you and [then] you will become My witnesses [i.e., to tell what you know] in Jerusalem, in [the countries of] Judea and Samaria, and [even] to the distant regions of the earth."
John 14:16-17
"And I will ask the Father and He will give you another Helper [i.e., besides me], who will be with you forever.
John 15:26
"But the Helper will come, that is, the Holy Spirit of truth [i.e., who reveals truth]. He comes from the Father and I will send Him to you from the Father. [When He comes] He will give testimony about me.
John 16:7-16
Yet I am telling you the truth: It will be helpful to you for me to go away. For unless I go, the Helper [i.e., the Holy Spirit] will not come to you. But if I go, I will send Him to you.
Acts 2:1-21
And when the day of Pentecost came [Note: This was a Jewish festival held fifty days following the Passover Festival. Lev. 23:15-21], they [i.e., the twelve apostles] were all gathered together in one place [i.e., their second story living quarters, 1:13 ?].