What preceded the first outpouring of the Holy Ghost and the beginning of many great outpourings?

Before being taken up, Jesus gave His disciples a last command.

"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." - Acts 1:4 KJV

"Then returned they unto Jerusalem from the mount called Olivet, which is from Jerusalem a sabbath day's journey. And when they were come in, they went up into an upper room, where abode both Peter, and James, and John, and Andrew, Philip, and Thomas, Bartholomew, and Matthew, James the son of Alphaeus, and Simon Zelotes, and Judas the brother of James." - Acts 1:12-13 KJV

"These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Jesus, and with his brethren." - Acts 1:14 KJV

These all CONTINUED with ONE ACCORD IN PRAYER AND SUPPLICATION.

[Acts 2:41, Acts 4:4, Acts 5:14, Acts 6:4,7]