The Trinity is a revealed mystery in the biblical sense of the word mystery. And it is not enough to list it alongside other mysteries, because it concerns the entire scope of salvation history and makes known the actual identity of God. As a doctrine covering territory so deep and wide, it is a mystery without peers; it is the one primordial mystery of God’s being and works. The triunity of God has always been, was once concealed, and is now revealed. The manner of its revelation should establish the order and structure of the doctrine concerning it, as well as the order and structure of adjacent doctrines like revelation and salvation (Fred Sanders, The Triune God, 68).