Acts 1:6-11 New Living Translation (NLT)
The Ascension of Jesus
6 So when the apostles were with Jesus, they kept asking him, “Lord, has the time come for you to free Israel and restore our kingdom?”
7 He replied, “The Father alone has the authority to set those dates and times, and they are not for you to know. 8 But you will receive power when the Holy Spirit comes upon you. And you will be my witnesses, telling people about me everywhere—in Jerusalem, throughout Judea, in Samaria, and to the ends of the earth.”
9 After saying this, he was taken up into a cloud while they were watching, and they could no longer see him. 10 As they strained to see him rising into heaven, two white-robed men suddenly stood among them. 11 “Men of Galilee,” they said, “why are you standing here staring into heaven? Jesus has been taken from you into heaven, but someday he will return from heaven in the same way you saw him go!”
Ascension Day is one of the earliest Christian festivals dating back to the year 68. According to the New Testament in the Bible, Jesus Christ met several times with his disciples during the 40 days after his resurrection to instruct them on how to carry out his teachings. It is believed that on the 40th day he took them to the Mount of Olives, where they watched as he ascended to heaven.
Ascension Day marks the end of the Easter season and occurs ten days before Pentecost. Depending upon the phases of the Moon in a particular year, Ascension Day is celebrated on a Thursday. However, some churches, particularly in the United States, celebrate it on the following Sunday.
Many Eastern Orthodox churches calculate the date of Pascha (Easter) according to the Julian calendar, rather than the Gregorian calendar used by many western churches, so their Ascension Day usually occurs after the western observance.