On Yom Kippur during Mincha [the afternoon of Yom Kippur] we read about the prohibition of forbidden relations in Parashat Acharei Mot:
אִישׁ אִישׁ אֶל־כָּל־שְׁאֵר בְּשָׂרוֹ לֹא תִקְרְבוּ לְגַלּוֹת עֶרְוָה אֲנִי יְהוָה׃ ס
עֶרְוַת אָבִיךָ וְעֶרְוַת אִמְּךָ לֹא תְגַלֵּה אִמְּךָ הִוא לֹא תְגַלֶּה עֶרְוָתָהּ׃ ס
עֶרְוַת אֵשֶׁת־אָבִיךָ לֹא תְגַלֵּה עֶרְוַת אָבִיךָ הִוא׃ ס
No man shall not approach his close relative to uncover nakedness; I am HaShem. The nakedness of your father and the nakedness of your mother you shall not uncover; she is your mother, you shall not uncover her nakedness. The nakedness of your father’s wife you shall not uncover; it is your father’s shame.
What does forbidden relations have to do with Yom Kippur that Vayiqra 18 is read during Mincha on Yom Kippur?
One could assume that maybe someone is guilty of violating one of the forbidden relations outlined in Vayiqra 18, but, if one person is guilty of incest, adultery or some other forbidden relationship why does the entire community have to be subjected to listening to the Torah being chanted about discreet sins they did not commit?
I would like to suggest two reasons why Vayiqra 18 is read on Yom Kippur, especially during Mincha.
1). Vayiqra 18 is not being simply read because it’s a part of the Parasha that highlights Yom Kippur. Rather Vayiqra 18 is being read as a prayer to HaShem where we are reminding G-d of His Word – that just as He asked us not to uncover the nakedness of another person [somebody who is close to us], i.e., exposing their sins. Likewise, we are asking HaShem not to expose our nakedness, not to expose our sins for the world to see.