Job has been kind of a gloomy guy, having his little pity parties, but then he gets his eyes off his pain and misery and on the big picture.
He begins to look beyond the here and now to things that will never change—things he can rejoice in.
Job knew that one day his body would change and he would see Jesus.
Job 19:25-27 For I know that my redeemer liveth, and that he shall stand at the latter day upon the earth: And though after my skin worms destroy this body, yet in my flesh shall I see God: Whom I shall see for myself, and mine eyes shall behold, and not another; though my reins be consumed within me.
I find a lot of comfort, hope and strength in the thought of having a perfect body and seeing Jesus.