כֹּֽה־אָמַ֨ר יְהוָ֜ה אֵלַ֗י הָל֞וֹךְ וְקָנִ֤יתָ לְּךָ֙ אֵז֣וֹר פִּשְׁתִּ֔ים וְשַׂמְתּ֖וֹ עַל־מָתְנֶ֑יךָ וּבַמַּ֖יִם לֹ֥א תְבִאֵֽהוּ׃
Thus said the LORD unto me: ‘Go, and get thee a linen girdle, and put it upon thy loins, and put it not in water.’
Rashi on Jeremiah
and do not put it in water to wash it when it will be soaked with sweat, in order that it hasten to decay.