The remaining eleven apostles are still together after the resurrection of the Messiah, and Jesus, who in a resurrection body, according to Acts 10:40-41, “becomes visible, not to all people, but to witnesses who were chosen beforehand, by Jehovah,” appears to them.
While on earth teaching His apostles Jesus told them in John 14: 26 that, “the Helper, the Holy Spirit, whom my Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you.” John 16:8 Jesus expands on the coming Holy Spirit, “it is to your advantage that I go away; for if I do not go away, the Helper will not come to you; but if I go, I will send Him to you.” (Note that the Holy Spirit is referred to in translation as the Helper, the Comforter, and the Advocate.)
Back to Acts 1:8-9, Jesus has His Apostles gathered at Mt. Olivet, verse 12. ‘a Sabbath days journey from Jerusalem,’ about one half mile away. It is there that He tells them, “you will receive power, when the Holy Spirit has come upon you; and you shall be my witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth.” After He said these things, He was lifted up while they were looking on, and a cloud received Him out of their sight.
The Resurrection of Jesus occurred on the day of First Fruits, a Feast for Israel commanded by Jehovah, and the event described above, the Ascension, was 40 days after the Resurrection. The Holy Spirit would come on Pentecost, 50 days after the Resurrection. In Israel’s history the 40 day mark would be the crossing of the Red Sea after their release from bondage to Egypt. Pentecost was the receiving of the Ten Commandments on Mt. Sanai. The historical significance of the crossing of the Red Sea is a complete separation from the past life of slavery to Egypt. There was no going back, as the waters of the Sea closed in behind them, only a new life was in store for them, they could not return. In like manner for the Apostles at this meeting with Jesus, at His Ascension, is the symbolic crossing over into new life in Christ. There is no going back into the slavery of sin.
Once a person is’ born again’ in Christ, he is a new creature, he is on the path to a changed life, and like Israel, who was set free from slavery, so is the one who is in Christ. Jesus fulfilled the Torah, (the Law), as Israel acted out and prophesied the coming Savior, from Moses, to the conquering of the god’s of Egypt, to the crossing of the Red Sea, to the manna, to the giving of the Law, to the water of life that poured out of the rock, to the entering of the Promised Land. Jesus satisfied the Torah by reenacting all the events of Israel in His life, bringing new life to all who believe, and we also receive the same promised Holy Spirit who indwells us, and strengthens us for ministry.