In short, Kannami's father, who was the samurai of the Hattori clan in Iga, received a message from Kasuga Myoujin (the deity of Kasuga-ji Shrine) to "have your son serve god as a musical performer" and because of this he had his third son, Kannami, change his name to Uzaki and offered him to Kasuga Myojin.
つまり、伊賀の服部氏一族の武士であった観阿弥の父が、あるとき春日明神より「子を楽人として神に仕えさせよ」との神託を受け、三男である観阿弥に結崎氏を名乗らせ春日明神に捧げたという。