“Thus said Yahweh to me.
‘Go!
Buy yourself a linen loincloth!
Put it on your loins!
But do not dip it in water!’
So I bought a loincloth
According to the word of Yahweh.
I put it on my loins.”
Yahweh told Jeremiah to buy a linen loincloth. We might consider it to be underwear, a bathing suit, or exercise shorts. However, Jeremiah was to wear this linen loincloth, but not go into the water with it. Jeremiah did what Yahweh had asked him to do. Thus he bought the loincloth and put it on. This seems like a nice simple message. Get new underwear!