וְיָתֵ֛ד תִּהְיֶ֥ה לְךָ֖ עַל־אֲזֵנֶ֑ךָ וְהָיָה֙ בְּשִׁבְתְּךָ֣ ח֔וּץ וְחָפַרְתָּ֣ה בָ֔הּ וְשַׁבְתָּ֖ וְכִסִּ֥יתָ אֶת־צֵאָתֶֽךָ׃
And thou shalt have a paddle among thy weapons; and it shall be, when thou sittest down abroad, thou shalt dig therewith, and shalt turn back and cover that which cometh from thee.
Read kabbalistic (mystical) interpretation of Deuteronomy 23:14: and classical mystical sources.