Halakhah su Deuteronomio 23:14

It is written: "You shall cover your excrement because Hashem, your God walks in the midst of your camp … your camp shall be holy and there should not be seen in you any unclean thing."¹Deuteronomy 23:14–15. From here our Sages, of blessed memory, infer that wherever Hashem, our God walks with us, meaning when we are engaged in a sacred matter such as reciting the Shema, or prayers, or study, Torah, or the like, the place must be holy. No uncovered excrement should be found there nor any nakedness be visible in the presence of the person reciting the Shema or praying.

It is forbidden to say or think about sacred matters in a place that contains feces or other foul-smelling substances, as the Torah states: “You will return and cover your excrement. This is because Lord your God walks among you in your camp…. Your camp must therefore be holy” (Devarim 23:14-15). This law contains many details, and we will learn only a few of them.

To Be Careful of Excrement at the Time of the Recitation of the Sh'ma. Containing 6 Se'ifim
Excrement [that is seen] through a [glass] lamp - it is permitted to recite in front of it even though one sees it through the [glass] walls [of the lamp] because the Mericful One conditions [it] on being covered, as is written "And you shall cover your excrement" (Deuteronomy 23:14), and here, it is covered.