Question: "What is Reformed Theology?"
Answer: Broadly speaking, Reformed theology includes any system of belief that traces its roots back to the Protestant Reformation of the 16th Century. Of course, the Reformers themselves traced their doctrine to Scripture, as indicated by their credo of "sola scriptura," so Reformed theology is not a "new" belief system but one that seeks to continue apostolic doctrine.
Generally, Reformed theology holds to the authority of Scripture, the sovereignty of God, salvation by grace through Christ, and the necessity of evangelism. It is sometimes called Covenant theology because of its emphases on the covenant God made with Adam and the new covenant which came through Jesus Christ (Luke 22:20).
Authority of Scripture. Reformed theology teaches that the Bible is the inspired and authoritative Word of God, sufficient in all matters of faith and practice.
Sovereignty of God. Reformed theology teaches that God rules with absolute control over all creation. He has foreordained all events and is therefore never frustrated by circumstances. This does not limit the will of the creature, nor does it make God the author of sin.
Salvation by grace. Reformed theology teaches that God in His grace and mercy has chosen to redeem a people to Himself, delivering them from sin and death. The Reformed doctrine of salvation is commonly represented by the acrostic TULIP (also known as the five points of Calvinism):
T - total depravity. Man is completely helpless in his sinful state, is under the wrath of God, and can in no way please God. Total depravity also means that man will not naturally seek to know God, until God graciously prompts him to do so (Genesis 6:5; Jeremiah 17:9; Romans 3:10-18).
U - unconditional election. God, from eternity past, has chosen to save a great multitude of sinners, which no man can number (Romans 8:29-30; 9:11; Ephesians 1:4-6,11-12).
L - limited atonement. Also called a "particular redemption." Christ took the judgment for the sin of the elect upon Himself and thereby paid for their lives with His death. In other words, He did not simply make salvation "possible," He actually obtained it for those whom He had chosen (Matthew 1:21; John 10:11; 17:9; Acts 20:28; Romans 8:32; Ephesians 5:25).
I - irresistible grace. In his fallen state, man resists God's love, but the grace of God working in his heart makes him desire what he had previously resisted. That is, God's grace will not fail to accomplish its saving work in the elect (John 6:37,44; 10:16).
P - perseverance of the saints. God protects His saints from falling away; thus, salvation is eternal (John 10:27-29; Romans 8:29-30; Ephesians 1:3-14).
The necessity of evangelism. Reformed theology teaches that Christians are in the world to make a difference, spiritually through evangelism and socially through holy living and humanitarianism.
Other distinctives of Reformed theology generally include the observance of two sacraments (baptism and communion), a cessationist view of the spiritual gifts (the gifts are no longer extended to the church), and a non-dispensational view of Scripture. Held in high esteem by Reformed churches are the writings of John Calvin, John Knox, Ulrich Zwingli, and Martin Luther. The Westminster Confession embodies the theology of the Reformed tradition. Modern churches in the Reformed tradition include Presbyterian, Congregationalist, and some Baptist.