After their glorious adventure on the ship The Dawn Treader, Lucy and Edmund come face to face once again with Aslan in the form of the Lamb. The children want to continue on from this thrilling adventure to the next. But Aslan, while assuring them that He will continue showing them Himself, sends them back to their own country, not even Narnia, but where their real home is.
Little Much Afraid, in Hinds Feet in High Places, after traveling with The Shepherd to the High Places must return to the Valley of sadness where real life is lived. Like the Pevensie children, she does have her pocket of pebbles turned jewels, i.e. memories of experienced blessed and redeemed by Aslan/The Shepherd.
After His resurrection, we find as reported by Luke in the book of Acts, the Lord appearing and then disappearing over a period of six weeks. During this time He is teaching his disciples and helping them to grow accustomed to the idea that He is with them, and will be with them whether visible or not.
Then these same men witness from a hill 'a cloud receiving Him out of their sight'.
They saw, and with the seeing came the knowing with certainty that death had been conquered.
They knew beyond doubt that their beloved Jesus [Aslan, Shepherd] was truly the Son of God.
And it was for them to return to their 'real world' with what they had witnessed. Luke states very clearly that they "returned to Jerusalem with great joy", not sadness at the let-down, but JOY.
There was no date given when they could follow and so be once again in His presence. But as Aslan told Lucy "..I will not tell you how long or short the way will be; only that it lies across a river. But do not fear that, for I am the great Bridge Builder...."
Thomas Cranmer sums it up nicely in his collect for Ascension Day:
Grant we beseech thee, almighty God,
that like as we do believe thy only begotten son our Lord
ascended into the heavens;
so we may also in heart and mind thither ascend,
and with Him continually dwell,
who liveth and reigneth with thee
and the Holy Ghost, one world without end.
Christ's absence is connected with our present. We may dwell with Him in heart and mind in our Now until such a time as we are brought from our country into His Country.
Like the disciples of old, may we tread the tedious streets of our present Jerusalem -this day- with Joy.