根据基督教教义名词，耶稣复活四十天后升上天堂。〈使徒行传〉第一章载，耶稣在四十天之内多次向使徒显现，此后，使徒见祂上升进入云端。基督教徒认为，耶稣升天有重大意义，这是因为他们相信，耶稣死而复活之后，要享荣耀并被高举，而且祂已回到天父身边。这一事情是为了指出耶稣和天父以及耶稣和信徒间的新关系。庆祝耶稣升天的仪式为全世界的信徒所遵循，这个庆祝仪式强调了基督的君王身分。从西元4世纪开始，将复活节（Easter）后第四十天，及圣灵降临节的前十天订为耶稣升天日。

In Christian¹ belief， the ascent² of Jesus into heaven 40 days after the Resurrection. The Book of Acts relates that， after several appearances to the Apostles over a period of 40 days， Jesus was taken up in their presence and hidden behind a cloud， a symbol of God's presence. The event is thought to indicate a new relationship between Jesus and God and between Jesus and his followers³. The feast of the Ascension is universally observed by Christians⁴， and its celebration emphasizes the kingship of Christ. Since the 4th century， it has been celebrated⁵ 40 days after Easter and 10 days before Pentecost.