A Ben Torah Is Careful Even About a Stain
Rav Pam asked of bnei Torah a special sensitivity in middos and in dealing with others, as befits a talmid chochom. He would point out that the Rambam writes that a talmid chochom should not walk around with even a stain on his shirt. If so, how much more must he be careful in how he speaks and acts, as befits a ben Torah.
Source: Quoting the Rambam