John 16:21

A woman when she is in travel, hath sorrow, because her hour is come; but when she is delivered of the child, she no longer remembreth the anguish, for joy that a man is born into the world.

Revelation 7:14-17

And he said to me, These are they who come out of great affliction, and they have washed their robes and made them white in the blood of the Lamb.

Treasury of Scripture Knowledge

Summary

Because thou shalt forget thy misery, and remember it as waters that pass away:

Bible References

Because

John 16:21
A woman when she is in travel, hath sorrow, because her hour is come; but when she is delivered of the child, she no longer remembreth the anguish, for joy that a man is born into the world.
Revelation 7:14
And he said to me, These are they who come out of great affliction, and they have washed their robes and made them white in the blood of the Lamb.