In Hebrew, anything said or written three times expresses the highest degree or quality. The reason the angels cry out, “Holy, holy, holy” is because they are declaring that the Lord is the One who exhibits maximum, complete, and ultimate holiness (Isa. 6:3). Since six represents the number of the physical world, 666 (the number six expressed to the highest degree) represents total materialism. It is complete physicality, earth apart from heaven.
The tripple nature of this statement is also reflective of the triune nature of God in that 7 is the number associated with God and 777 with the triune nature of God.
