John 16:21

When a woman is in labor she is sorrowful, for her time has come; but when the child is born, she forgets her pain in her joy that a human being has been brought into the world.

Revelation 7:14-17

I said to him, "You know, my lord." He said to me, "They are the people who come through the great persecution, who have washed their robes 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
When a woman is in labor she is sorrowful, for her time has come; but when the child is born, she forgets her pain in her joy that a human being has been brought into the world.
Revelation 7:14
I said to him, "You know, my lord." He said to me, "They are the people who come through the great persecution, who have washed their robes white in the blood of the Lamb.