“Holy One of God” is the title that some demons used of Jesus (Yeshua‘). Although they wanted nothing to do with Jesus, they were nonetheless afraid of Him and came under His authority when He cast them out. Demons have 20/20 vision into spiritual truth and they tremble at that truth.
In John’s gospel, Peter also called Jesus by this name.
Holy One of God in Greek:
Ho hagios tou Theou
Strong’s Concordance numbers: 40, 2316
Bible references: Mark 1:24; Luke 4:34; John 6:69 (not Amp, KJV)
When Jesus encountered a man with an unclean demon in the synagogue in Capernaum, the demon responded immediately:
“Let us alone! What business do we have with each other, Jesus of Nazareth? Have You come to destroy us? I know who You are—the Holy One of God!” (Luke 4:34)
In the King James and the Amplified versions of the verse in John, the demon calls Jesus “the Christ, the Son of the living God.” These words reflect the variation in the Greek manuscripts containing this verse.
Similar names of Jesus are Holy Servant and Holy and Righteous One. God is referred to as the Holy One and the Holy Father.