Isaiah 60:19-20 (HCSB)

The sun will no longer be your light by day,
and the brightness of the moon will not shine on you;
but the Lord will be your everlasting light,
and your God will be your splendor.
 Your sun will no longer set,
and your moon will not fade;
for the Lord will be your everlasting light,
and the days of your sorrow will be over.

     The Lord will be your everlasting light.  What need for the sun and moon when God the Father will be the light in our eternal dwelling with him?  John fleshes out this truth in Revelation: Revelation 22:5 (HCSB)  Night will no longer exist, and people will not need lamplight or sunlight, because the Lord God will give them light. And they will reign forever and ever.
     The day is coming when our days of sorrow will indeed be over and we will be forever with The Lord in his dwelling place.
Calvin: But we ought not to judge of the Church from the dangers of the present life; for she is preserved in the midst of the billows; as if he had said, “Do not judge of thy safety from the present appearance of things, but know that it is laid up in God.