Question: What is meant by "sides of the pit" in Isaiah 14:15? Thank You!
Response: Hebrew poetry (and Isaiah 14 is in poetic form) is often composed of parallel expressions (e.g., Prov.14:19: "Evil men will bow down in the presence of the good, AND the wicked at the gates of the righteous"). In such instances, the two parallel phrases or sentences serve to reinforce each other, or explain each other. Is.14:15 is such a case, where being "brought down" a) to the grave (or lit. sheol ) and b) to the sides of the pit, mean the same thing: Satan will be cast into Hades, that is, the Abyss. The "sides" part is often translated "depths", for the Hebrew yarchah in addition to meaning "side/flank" can, in their way of thinking about things, mean the IN-side, or most protected, or "uttermost" part (hence, the very bottom). So this is poetic language for "you will be utterly cast into hell".
Please also see these links:
Is Sheol an actual place?
The Heavenly Sea
Christ's Preaching to the Spirits in Hell
What does the Bible say about Heaven and Hell?
Yours in Christ,