John 16:21

a woman when she is in travail, is afflicted at the approach of her pains: but as soon as she is delivered of the child, the remembrance of her anguish, is lost in her joy, that a man is born into the world.

Revelation 7:14-17

my Lord, answer'd I, you can tell. and he said to me, these are they who came out of great tribulation, and 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 travail, is afflicted at the approach of her pains: but as soon as she is delivered of the child, the remembrance of her anguish, is lost in her joy, that a man is born into the world.
Revelation 7:14
my Lord, answer'd I, you can tell. and he said to me, these are they who came out of great tribulation, and have washed their robes, and made them white in the blood of the lamb.