On p. 35a of Matsref la-Ḥokhmah (first ed., in Likutim Shonim, Basel, 1629), Joseph Solomon Delmedigo writes:
Know that the angels called ishim are far from the Glory and close to the spheres of the elements, and thus it is easier for them to be enclothed in human form than it is for those angels that are close to the Glory of the Shekhinah. Their name attests to their nature, for they are called ishim, as is explained in the Sefer ha-Merkavah.
Does anyone know what book or writing Delmedigo is referring to here under the name of Sefer ha-Merkavah?
I will be grateful for any information.
University of Arkansas