ויאמר כו' של נעליך מעל רגליך כו' אדמת קודש הוא. וזהו נעליך, מלשון נעילת דלת שאתה קשור ומחובר תמיד למעלה מעל רגליך שהוא רגיל תמיד להיות מחשבתו דבוק למעלה, כי המקום כו' אדמת קודש, קודש מורה על החכמה ועליות נצוצות הם למטה:
To prepare Moses for his sacred mission, God commanded: Remove the shoes from upon your feet, for the place on which you stand is holy ground! (Ex. 3:5) But the word נעלים, “shoes,” has a dual meaning. The word נעלים is related to ת דלתנעל, “locking up a door.” Moses’ shoes were a symbol of the things that had kept him “locked up” and unable to detect God's presence in the everyday world. Moses had to "unlock" himself in order to become connected with the world around him and grow into an effective leader. In this way, Moses learns that holiness can be found on earth; the burning bush was one of the “sparks” from the Most High which exists in our earthly domain.
Rabbi Levi Yitzhak of Berditchev, 19th c. Ukraine