'Loins' in the Bible

No one among them is weary or stumbles,No one slumbers or sleeps;Nor is the belt at their waist undone [as if unprepared for action],Nor is the strap of their sandal broken.

And righteousness will be the belt around His loins,And faithfulness the belt around His waist.

at that time the Lord spoke through Isaiah the son of Amoz, saying, “Go, untie the sackcloth from your hips and take your sandals off your feet.” And he did so, walking around stripped [to his loincloth] and barefoot.

Therefore [continues Isaiah] my loins are filled with anguish;Pains have seized me like the pains of a woman in childbirth;I am so bent and bewildered that I cannot hear, I am so terrified that I cannot see.

Tremble, you women who are carefree;Tremble with fear, you complacent ones!Strip, undress and wear sackcloth on your waist [in grief],

This is what the Lord says to His anointed, to Cyrus [king of Persia],Whose right hand I have heldTo subdue nations before him,And I will ungird the loins of kings [disarming them];To open doors before him so that gates will not be shut: