Musar for Sanhedrin 76:19
אמר רב נחמן האי מאן דידע לאהדורי למינים כרב אידית ליהדר ואי לא לא ליהדר אמר ההוא מינא לרב אידית כתיב (שמות כד, א) ואל משה אמר עלה אל ה' עלה אלי מיבעי ליה א"ל זהו מטטרון ששמו כשם רבו דכתיב (שמות כג, כא) כי שמי בקרבו
Even as it has been taught: One was for Himself and one for David: this is R. Akiba's view. R. Jose protested to him: Akiba, how long will thou profane the <i>Shechinah</i>?<span class="x" onmousemove="('comment',' By asserting that a human being sit beside Him. ');"><sup>50</sup></span> Rather, one [throne] for justice, and the other for mercy. Did he accept [this answer] from him or not? Come and hear! For it has been taught: One is for justice and the other for charity; this is R. Akiba's view. Said R. Eleazar b. Azariah to him: Akiba, what hast thou to do with Aggada? Confine thyself to [the study of] Nega'im and Ohaloth.<span class="x" onmousemove="('comment',' Names of Treatises in the Seder Tohoroth, the most difficult in the whole of the Talmud. V. infra 67b. R. Akiba was a great authority on these laws, whereas his Haggadic interpretations were not always acceptable. [This interpretation involved the same danger as that of R. Akiba's first interpretation in that it tended to obscure the true monotheistic concept of God.] ');"><sup>51</sup></span> But one was a throne, the other a footstool: a throne for a seat and a footstool in support of His feet.