'Bitterness' in the Bible

“What shall I say?For He has spoken to me, and He Himself has done it;I will wander aimlessly all my years because of the bitterness of my soul.

“Indeed, it was for my own well-being that I had such bitterness;But You have loved back my life from the pit of nothingness (destruction),For You have cast all my sins behind Your back.