The following is Thomas Torrance giving an account of what Karl Barth thinks theology is. The context of this quote is discussing the relationship that Barth sees between philosophy and theology.
. . . Theology is not free thought, but is thought bound to its object, thought that does not move in any direction that it chooses but in a direction chosen for it by the activity of the object in his sovereign self-giving and self- revelation. Theology is thinking bound to God who communicates himself in his Word to the Church to be recognised and known as God. The self-giving, self-communicating, the speaking on the part of God calls for a corresponding activity on the part of theology in receiving, appropriating and hearing. Its knowledge is gained by way of obedience; it is thought out, not from a center in itself, but from a center beyond itself, in God, or rather, it is not knowledge that is first thought out, but knowledge that is thought in because it is derived from hearing. (Thomas F. Torrance, “Karl Barth: An Introduction to His Early Theology 1910-1931,” 150)