Musar zu Dewarim 23:14

Among the [negative commandments] that are dependent on the (heart) [tongue] are: “Since the Lord, your God, moves about in your camp to protect you and to deliver your enemies to you, let your camp be holy; let not anything unseemly be seen among you” (Deuteronomy 23:15). They, may their memory be blessed, said (Berakhot 25b) that included in this [prohibition] is that when we speak words of the Torah of God, may He be blessed - and in our speaking in prayer in front of Him - our camp should be holy, and let not anything unseemly be seen among us. Therefore we were commanded about this, to mention [God’s] name in holiness and to engage in words of Torah and prayer in holiness; and not to mention [God’s] name or words of Torah if he is naked or if there is a naked man across from him. And likewise were we warned that the place be clean, as it is stated (Deuteronomy 23:14), “you shall dig a hole with it and cover up your excrement.” And all the more so is he warned not to mention [God’s] name if his hands are not clean. And if his hands touched something disgusting to him, he should wash them - like the matter that is stated (Psalms 26:6), “I wash my palms in cleanliness.” And when one is walking on the path and he is in doubt if the path is clean, he should not mention [God’s] name, and he should not say words of Torah. And if there is something that is not clean behind him - such as excrement or a carcass or water [used for] soaking [flax] - one must move a distance of four ells away from where the odor ends; but in front of him, [the distance] is [as far as] his eye can see. And carefulness about this is one of the ways of fearing God, as it is stated (Malachi 3:16), “concerning those who revere the Lord and esteem His name.” And our Rabbis, may their memory be blessed, said (Berakhot 24b), “‘For he has shown contempt for the word of the Lord’ (Numbers 15:31) - this is [referring to] one who says words of Torah in filthy alleyways.” And our Rabbis, may their memory be blessed, said (Kohelet Rabbah 1:17), “‘He gives wisdom to the wise’ (Daniel 2:21) because the wise honor the Torah and occupy themselves with it in holiness.” But if He had given it to the silly, they would have said words of Torah in filthy alleyways.

(Devarim 23:14): "And a peg shall there be for you al azenecha": Bar Kappara expounded: Read it not "al azenecha" ["among your implements"], but "al aznecha" ["upon your ears"]. If one hears something unseemly, let him place his fingers in his ears? [That is, if he understands that they are going to speak of such things, or if he does not want to hear anymore.] This is as R. Elazar said: "Why are a man's fingers like pegs? So that if he hears something unseemly, he can place his fingers in his ears." It was taught in the school of R. Yishmael: "Why is the ear itself stiff, and the lobe soft? So that if one hears something unseemly, he can place his lobe in his ear." The Rabbis taught: "Let one not permit his ears to hear idle talk, for they are the first to be 'burnt' of all the organs."