Of the Trinity

We do believe that God is one, most singly and singularly one, and an only one: The unity of the Godhead is… a most singular unity…, All three Persons have one and the same single and infinite Godhead, and therefore must needs mutually subsist in one another, because they are all three one and the same infinite God… united in their one nature, not confounded in their distinct¬†substances; nay though their subsistence is in one another, yet their subsistences are distinct, but the nature most singularly the same.
— Francis Cheynell
Quoted Joel R. Beeke & Mark Jones in A Puritan Theology: Doctrine for Life.