Classical theism is the term applied to an old concept of God which states that he is the ultimate cause of all things, that he is non-contingent, and that he is the transcendent being upon which all reality depends.  He is the uncaused cause, the terminus, the non-contingent first cause of all things.  Ancient Greeks believed this. The Muslims do, too, along with the Jews and Jehovah’s Witnesses. In fact, I regularly assume this idea that all events stand in causal relation to God in many of my impromptu debates with atheists in online discussions. Nevertheless, let’s take a look at some definitions of the term means.

“Classical theism is found in the Greeks since Plato; in the Judaism of Philo, Maimonides, and others; in Christian orthodoxy generally, and in Islam as early as al-Kindi.”
https://iep.utm.edu/god-west/

“Classical theists view God as the metaphysically necessary foundation of all reality…he is the fundamental reality on which all things depend for their being at anymoment.”
http://www.classicaltheism.com/wp-content/uploads/2019/07/What-is-Classical-Theism_-by-Mead.pdf

“According to the classical theism of Augustine, Anselm, Aquinas and their adherents, God is radically unlike creatures and cannot be adequately understood in ways appropriate to them. God is simple in that God transcends every form of complexity and composition familiar to the discursive intellect. One consequence is that the simple God lacks parts.”
  https://plato.stanford.edu/entries/divine-simplicity/

Is classical theism biblical?

But classical theism is not enough by itself.  In Christianity, God is a trinity. Classical theism, which is focused on God as the ultimate, non-contingent cause, does not describe the Trinitarian nature of God revealed in the Bible.  Of course, there are Trinitarian to hold to this view classical theism – myself included. But I don’t stop at the classic theism definition. I assume the totality of biblical revelation is true, that God is a Trinity, and that all things ultimately make sense only in the Trinitarian foundational perspective. Note, I deny the idea the non-Trinitarian God-concept can account for our existence, the universality of truth, the transcendental laws of logic, and the issues concerning “the one in the many.”

So, classical theism is within biblical orthodoxy and is not sufficient to represent proper biblical theology.