Shalak (שָׁלַךְ) means to throw, cast, or fling — objects, people, words, or even God's relationship to sin. It appears about 125 times in the Old Testament. The range of uses includes throwing Joseph into a pit (Genesis 37:20), casting idols away (Isaiah 30:22), and most powerfully, God casting sins into the depths of the sea (Micah 7:19).
The most theologically significant use of shalak is in Micah 7:19: 'You will cast [shalak] all our sins into the depths of the sea.' This is one of the most complete images of forgiveness in the Old Testament — sins thrown into the deepest part of the ocean, beyond recovery. Isaiah 38:17 uses similar language: 'You have put all my sins behind your back.' Psalm 22:10 uses shalak for being 'cast upon God' from birth, denoting utter dependence. The same word that describes throwing away trash describes God throwing away our sins. What we desperately cling to as condemnation, God hurls into the abyss.