מלאכי ג:ב פירוש: רש״י

Now who can abide This is synonymous with; וּמִי יָכִיל

and who will stand Will be able to stand.

and like fullers’ soap Like soap used by the fullers, which removes the entire stain. So will he remove all the wickedness. and like soap It is an herb which removes stains, erbe savonijere in Old French, probably soapwort. The word בֹּרִית signifies a thing that cleans and purifies, as in (Ps. 73:1), “to the pure of heart.”