בַּיּ֣וֹם הַה֗וּא יִֽהְיֶה֙ עַל־מְצִלּ֣וֹת הַסּ֔וּס קֹ֖דֶשׁ לַֽיהוָ֑ה וְהָיָ֤ה הַסִּירוֹת֙ בְּבֵ֣ית יְהוָ֔ה כַּמִּזְרָקִ֖ים לִפְנֵ֥י הַמִּזְבֵּֽחַ׃
In that day shall there be upon the bells of the horses: HOLY UNTO THE LORD; and the pots in the LORD’S house shall be like the basins before the altar.
Read kabbalistic (mystical) interpretation of Zechariah 14:20: and classical mystical sources.