Arising out of the crucible of christological and theological debates in the early centuries of the church, the Christian doctrine of the Trinity expresses the mystery of God that is the heart of all revelation. The philosophical cast and categories of these later disputes transposed the biblical material into very different idioms and discourses animated by rather different concerns. While they were concerned faithfully and fully to articulate the material truth of the biblical doctrine of the Trinity, the philosophical vantage points from which they did so were not, for the most part, native to — or at least typical of — the Scriptures themselves.
The result is a doctrine that speaks to deep realities that are often only penumbral to the revelation of Scripture itself, within which the sort of philosophical concerns regarding being that would exercise later theological minds emerge only sporadically and tangentially. Although the truth of the Trinity is materially present within Scripture, it requires a sort of discourse that proceeds according to different — and largely extra-scriptural — principles of investigation for that truth to come into crisp doctrinal focus.
But the doctrines of the Trinity and the Incarnation as stated in the Creed and as defined by the Ecumenical Councils of the fourth and fifth centuries clearly do not repeat Scripture. Nor can they be deduced from Scripture without the aid of some definitions of the philosophical terms that occur in the Creed, such as [ousia] (substance), [hypostasis] (individual), [physis] (nature), and so on. Even so, they can be rendered consistent with certain scriptural passages only if those passages are read in a none too natural way.
— Richard Swinburne, Oxford Handbook of Philosophical Theology, ed. Thomas P. Flint, Michael C. Rea, pp. 18, Oxford University Press, 2009.