The Hebrew navel (H5034) carries two intertwined meanings: to wither/fade (like a plant dying) and to dishonor/treat as vile (to nabal β treat with contempt). Isaiah 1:30 uses it of withering leaves: 'You will be like an oak with fading leaves, like a garden without water.' Isaiah 64:6 declares: 'All of us have become like one who is unclean... we all shrivel up like a leaf.' The connection between fading and foolishness is rooted in the same root as nabal (fool).
The theological depth of navel lies in its double meaning. Physical withering and moral foolishness/disgrace are linguistically linked in Hebrew thought. The fool (nabal, like Nabal in 1 Samuel 25) is the one who has withered spiritually β who has lost the sap of covenant relationship with God. Isaiah 40:7-8 contrasts this: 'The grass withers and the flowers fall... but the word of our God endures forever.' Human glory is navel β it fades. God's word is the only thing that does not wither.