It means that AME no Tarishihoko called heaven his older brother and the sun his younger brother, and his name was the reverend and noble son coming down to earth from heaven, associating tenson korin (descent of the heavenly grandchild).
阿毎多利思北孤は天を兄とし、日を弟とし、その名は天より垂下した尊貴な男子という意味で、天孫降臨を思わせる。