After the resurrection Jesus appeared to His disciples many times during a
period of forty days.
The ascension of Jesus is the teaching that Jesus left the earth by
ascending up through the clouds.
He ascended in full view of followers who wrote of what they saw.
SEEKINGJESUS.COM
After he said this, he was taken up before their very eyes, and a cloud hid
him from their sight. 10 They were looking intently up into the sky as he
was going, when suddenly two men dressed in white stood beside
them. 11 “Men of Galilee,” they said, “why do you stand here looking into
the sky? This same Jesus, who has been taken from you into heaven, will
come back in the same way you have seen him go into heaven.” (Acts
1:9-11 NIV)
When Jesus returns to earth He will not return as a baby in a manger like
the first time He came. He will be coming back in the same way that He
left, coming through the clouds.
According to the Lord’s own word, we tell you that we who are still alive,
who are left till the coming of the Lord, will certainly not precede those who
have fallen asleep. {16} For the Lord himself will come down from heaven,
with a loud command, with the voice of the archangel and with the trumpet
call of God, and the dead in Christ will rise first. {17} After that, we who are
still alive and are left will be caught up together with them in the clouds to
meet the Lord in the air. And so we will be with the Lord forever.
{18} Therefore encourage each other with these words. (1 Thess. 4:15-18
NIV)