From the Oxford English Dictionary:
Theology - The study of the nature of God and religious belief.
Systematic - Done or acting according to a fixed plan or system; methodical.
Systematic Theology - A form of theology in which the aim is to arrange religious truths in a self-consistent whole.
Biblical - Relating to or contained in the Bible.
From the Merriam Webster Dictionary:
Biblical theology - Theology based on the Bible; specifically: theology that seeks to derive its categories of thought and the norms for its interpretation from the study of the Bible as a whole.
Berkhof defined his discipline in this way:
Systematic theology seeks to give a systematic presentation of all the doctrinal truths of the Christian religion.
The systematician must show that every part of systematic theology strikes its roots deep down into the subsoil of Scripture.
Systematic theology is a discipline which addresses theological topics one by one (e.g. God, Sin, Humanity) and attempts to summarize all the biblical teaching on each particular subject.
John Frame: Author of SYSTEMATIC THEOLOGY
Systematic theology differs from exegetical theology (the application of specific passages), biblical theology (the application of the history of redemption described in Scripture). Systematics applies Scripture to “whole Bible” questions: e.g., what does the whole Bible teach about God’s love, or sanctification, or the Christian’s use of the internet’.
From the above we see that ‘Systematic Theology’ divides the Bible up into ‘subjects’. I see no practical difference between Systematic and Biblical Theology if the theology is restricted to the scriptures and excludes man-made philosophy. The Bible is the only source of knowledge about God.
The scriptures are the inspired word of God.
2 Timothy 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 17 That the man of God may be perfect, throughly furnished unto all good works.
From the Bible we must determine ‘doctrine’; which breaks the teaching of the Bible into subjects and precepts by which we should live our lives.
Membership of a Church is not a ‘free for all’. Members must agree on certain fundamental doctrines in order for a church to function.
Acts 2: 41 Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls. 42 And they continued stedfastly in the apostles’ doctrine and fellowship, and in breaking of bread, and in prayers.
The listing of these doctrines is called a Statement of Faith. A Statement of Faith is the result of a systematic study of the Bible to determine what God requires from us in both belief and practice.
1 Timothy 4:16 Take heed unto thyself, and unto the doctrine; continue in them: for in doing this thou shalt both save thyself, and them that hear thee.
The Christadelphian Statement of Faith (please click on the title to view)
I conclude that genuine Biblical Theology must of necessity be Systematic in order to have a practical effect in our lives.
I hope you find this helpful.