The Hebrew noun etsem means bone, skeleton, or body, and by extension, 'the very self' or essence of something. It appears over 125 times in the Old Testament. The phrase etsem le-etsem (bone to bone) expresses the closest possible identification and solidarity.
When Adam sees Eve for the first time, he exclaims: 'This is now bone of my bones and flesh of my flesh' (Genesis 2:23) — the idiom expressing that she is his very counterpart, sharing his nature completely. This profound statement of unity becomes the basis for the marriage covenant. Etsem in prophetic contexts can describe the dried bones of the spiritually dead: Ezekiel's vision of the valley of dry bones (Ezekiel 37) portrays Israel's exile as scattered bones — dead, disconnected, hopeless — until the breath of God brings new life. The Psalmist uses etsem to describe inner suffering: 'My bones wasted away through my groaning all day long' (Psalm 32:3). Proverbs 17:22 observes that 'a crushed spirit dries up the bones.' The resurrection hope also connects to bones: Psalm 34:20 says 'he protects all his bones, not one of them will be broken' — cited in John 19:36 as fulfilled at the crucifixion.