Biblical Theology is the name given, especially in Germany, to a branch of scientific theology, which has for its object to set forth the theology of the Bible without reference to ecclesiastical or dogmatical formulas or creeds. (We make large use in this article of Nitzsch's article in Herzog's Real-Encyclopedia, vol. i.)
The name Biblical theology can be taken (as is the term theology in general) in a narrower and a wider sense, the narrower including only the sum of religious doctrine contained in the Old and New Testament Scriptures; the wider comprehending the science of the Bible in all the respects in which it may be made the object of investigation. Usually it is taken in the narrower sense, and some writers prefer, therefore, the name Biblical dogmatics.
As may be seen from the definition, Biblical theology has a very clearly defined relation to exegetical and historical theology no less than to systematic theology. It is the flower and quintessence of all exegetical investigations, for the very object of exegesis is to find out, with entire clearness, the true teaching of the word of God with regard to His own nature and the relations of man to Him. Its relation to historical theology is that of the foundation to the superstructure, for both the History of Doctrines and the History of the Church must set out with a fixed view of the teaching of the Scriptures as to the fundamental questions of religion. So, too, Systematic Theology, while it includes the statements of doctrine made in the creeds and formulas of the Church, must yet rest ultimately upon the authority of the Scriptures.
⇒See also the International Standard Bible Encyclopedia.