God is one but triune

God gives us information about himself.
Isaiah 6:3: "holy, holy, holy". Why is this repeated three times? Numbers 6:24-26: God blesses his chosen people.

He explains the idea of trinity in Luke 1:36. The being of man consists of three things: soul, spirit and body. It is comparable to the aggregate phases. Originally (from syriac-aramaic) trinity meant that one person has several charateristics, but it didn't mean that there where different people.