וַיֹּ֨אמֶר הַמֶּ֜לֶךְ לָהֶ֗ם קְח֤וּ עִמָּכֶם֙ אֶת־עַבְדֵ֣י אֲדֹנֵיכֶ֔ם וְהִרְכַּבְתֶּם֙ אֶת־שְׁלֹמֹ֣ה בְנִ֔י עַל־הַפִּרְדָּ֖ה אֲשֶׁר־לִ֑י וְהוֹרַדְתֶּ֥ם אֹת֖וֹ אֶל־גִּחֽוֹן׃
Der König sprach zu ihnen: Nehmet mit euch die Diener eures Herrn und lasset meinen Sohn Salomo auf meiner Mauleselin reiten und führet ihn hinab an den Gihon.
Rashi
On my personal mule. This will be a sign that he will reign and the beginning of [his] greatness, because a commoner is forbidden to ride on the king’s horse.
Ralbag
upon mine own mule: This is one of the symbols of kingship, that no one should ride on the king's chariot who is not a king.
Rashi
To Gichon. [Gichon] is the well of Shilo’ach. From this [episode is derived the custom] not to anoint the kings except at the well, to symbolize thereby that his kingship shall continue on and on.27As the waters of a well do.