Exodus 3:5

של means DRAW OFF and take off. It is of the same root as, (Numbers 19:5) “and the iron-head slippeth off (נשל) from the handle”; (Deuteronomy 28:40) “for thine olives shall drop off (ישל)‎”. אדמת קדש הוא the place IS HOLY GROUND (i. e. the masculine pronoun הוא refers to the word המקום and not to אדמת, which is feminine).

וַיֹּ֖אמֶר אַל־תִּקְרַ֣ב הֲלֹ֑ם שַׁל־נְעָלֶ֙יךָ֙ מֵעַ֣ל רַגְלֶ֔יךָ כִּ֣י הַמָּק֗וֹם אֲשֶׁ֤ר אַתָּה֙ עוֹמֵ֣ד עָלָ֔יו אַדְמַת־קֹ֖דֶשׁ הֽוּא׃

And he said, Do not come near: put off thy shoes from off thy feet, for the place on which thou dost stand is holy ground.