Theology is most simply described as the study of God. In this circumstance theology should be further defined by adding that it is Christian or Evangelical theology being examined. There are multiple approaches to Christian theology which include systematic, Biblical, dogmatic, and historical theology among others. The Moody Handbook of Theology defines theology by writing,
“The term theology is derived from the Greek theos, meaning “God,” and logos, meaning “word” or “discourse”; hence, “discourse about God.” The word systematic comes from the Greek verb sunistano, which means “to stand together” or “to organize”; hence, systematic theology emphasizes the systematization of theology.”
It may appear at first glance that the Bible believing theologian would only emphasize Biblical theology. But when these two methods are examined similarities are found and a need to have both methods used becomes apparent. Also, both of these methods do focus on the Bible. The Moody Handbook makes this point writing, “There are both similarities and differences between biblical and systematic theology. Both are rooted in the analysis of Scripture, although systematic theology also seeks truth from sources outside the Bible.” Both methods analyze Scripture but the systematic method specifically allows for the examination of outside sources and also relies on the exegetical work of the Biblical approach. Eric Millard describes this relationship writing,
When we inquire regarding the relationship of systematic theology to other doctrinal endeavors, we find a particularly close relationship between systematic theology and biblical theology. The systematic theologian is dependent on the work and insights of the laborers in the exegetical vineyard.In fact many theologians have found the need of a systematic theological method. Hodge is one such theologian. Hodge argued for the necessity of systematic theology using several fine points. Speaking of the systematic method he wrote that, “A much higher kind of knowledge is thus obtained, than by the mere accumulation of isolated facts.” He further explained by writing, “[God] gives us in the Bible the truths which, properly understood and arranged, constitute the science of theology.” It is clear that Christians can benefit from the arranging of Biblical knowledge into a system where Bible knowledge is grouped into doctrinal classifications. Over history, eleven of these classifications have come to be the key or primary topics of theology. This work will give a basic description of each of these topics.
Theology Proper: The first topic of systematic theology is known as “theology proper.” Theology proper seeks to define the doctrines of God apart from Christology, and Pneumatology. Chafer defines theology proper as “A consideration of the facts concerning God—Father, Son, and Spirit, apart from their works.” Enns further defines this topic writing;
Theology proper is a category of study within systematic theology; it denotes the study of the nature and existence of God. To distinguish the study of God specifically (in contrast to the study of Jesus Christ, the Holy Spirit, the church, etc.), the term proper is used to distinguish the study of God from theology in general.
Emphasis of this topic of theology is placed on the various attributes of God. It includes that He is the only God (Isa. 43:10), that He is triune in nature (1 John 5:7), aseity (Ps 90:2), among many other attributes.
Christology: simply is “the doctrine respecting the Lord Jesus Christ.” These doctrines define for the believer the person and nature of Jesus Christ. These doctrines include His Preexistence; (Col. 1:16; Heb 1:2), incarnation; (John 1:14 the word became flesh), and the deity of Christ as shown by His superiority and preexistence to Abraham (John 8:58). This is further shown by the acknowledgment that He is the image of the Father (John 14:9).
Pneumatology: is “the scientific treatment of any or all facts related to spirit.” The Holy Spirit is the third person of the Trinity and therefore is deity. A study of the Holy Spirit would not be complete without a clear examination of His deity and His existence within the Holy Trinity. Enns wrote that “The deity of the Holy Spirit is inextricably bound up with the doctrine of the Trinity. A denial of one is a denial of the other. Conversely, belief in the Trinity necessitates a belief in the deity of the Holy Spirit.” Chafer summarized some of the key doctrines of the Holy Spirit and passages that support these doctrines writing;
The Spirit is eternal (Heb. 9:14). He is omnipresent, since He is said to dwell in every believer (1 Cor. 6:19). He is omniscient. He it is who searcheth all things, even the deep things of God (1 Cor. 2:10). He is one of supreme majesty, for to vex Him, to do despite to Him, or to blaspheme Him, is sin in its most serious form. He giveth life (John 6:63). He inspires the Scriptures (2 Tim. 3:16); He teaches (John 16:13); He regenerates (John 3:6); He is the Spirit of “truth,” of “grace,” and He is holy, being especially honored with that descriptive title.
Bibliology: is the study of doctrines related to Scripture. The Bible authenticates itself as the special revelation of God that is given to men as His divinely inspired message to man (2 Tim 3:16-17). As God’s inspired message it is without error. Ryrie explains God’s revelation writing “the revelation in the Bible is not only inclusive yet partial; it is also accurate (John 17:17), progressive (Heb. 1:1), and purposeful (2 Tim. 3:15–17).” Scripture provides the context for salvation and for living a Godly life.
Angelology: is the study of angels. This study includes an examination of the origin (Gen. 1:31), number (Heb. 12:22; Rev. 5:11), and nature of angels. Angelology can include the study of fallen angels or demons while some separate this study from that of angelology. This study looks at the classifications of angels (Is. 6:2, 6; Gen 3:24). This is a critical study to understand spiritual warfare.
Anthropology: is one of the most important studies found in systematic theology. It is the study of man. Systematic theology seeks to organize all important topics of theology, therefore it must include a detailed analysis of man; after all, man is a primary emphasis of the Bible. Chafer wrote that “Systematic Theology incorporates logically every other science, so Anthropology incorporates all that enters into man’s being—that which is material and that which is immaterial, and, were it wise so to extend it, various disciplines which are important branches of science would be included, among these much of biology and more of psychology. Because of the intricacies of the latter and its likeness to the realm of spirit existence, that which enters into psychology naturally receives the greater emphasis.” The study of the doctrines of man includes the origin of man or his creation (Gen. 2:19) in the image of God (Gen. 1:27; 9:6). This study also includes man’s fall, his ability, freewill, and sin nature.
Hamartiology: is the study of the doctrines of sin and is commonly tied to anthropology. The study of sin can only be done by examination of Scripture since sin is not living up to the standards of the God of the Bible. Much of the Bible is devoted to this point. For example; Romans 3:23 states that the all have sinned and not reached the glory of God and the consequence for that sin is death (Rom. 6:23) and that sin can be recognized because of law (Rom. 7:7).
Soteriology: is the study of the doctrines of salvation. Hodge gives a thorough definition writing that soteriology includes “the purpose or plan of God in reference to the salvation of man; the person and work of the Redeemer; the application of the redemption of Christ to the people of God, in their regeneration, justification, and sanctification; and the means of grace.” These doctrines are tied directly to those of Christology. A study of soteriology reveals much about the nature of God. It shows that He is righteous and must judge sin while He also chose to provide grace to His creation. God could not just look away from sin and pretend it did not exist; therefore, He sent His Son (John 3:16) to be a propitiation or appeasement for the sin (Rom. 3:25; Heb 2:17; 1 John 2:2, 4:10).
Israelology: is a relatively new development is systematic theology and seeks to study the doctrines of Israel. These doctrines were previously included in the study of ecclesiology. This study defines the origin and importance of Israel in the past, present and future (Gen. 12:1-3; Rom. 11:25).
Ecclesiology: is a study of the doctrines of the church. These studies seek to define the church as well as explain its origin, purpose (past, present, and future), and distinctions from Israel. The church is made up of all believers in Jesus Christ from His death until the rapture of the church. Until then, the church is to act as the body of Christ (1 Cor. 12:27) at which time the church will be married to the bridegroom as the bride of Christ (Rev. 21:9) and will sit on a throne along with Jesus (Rev. 3:21). The church is a unique organism found only in this dispensation, which is a parenthetical time period which does not advance Israel’s prophetic plan.
Eschatology: is the study of the last things or the end times. This topic studies the doctrines of prophecy as they relate to the end times. Much of eschatology is tied to Israelology as well as ecclesiology. This theological topic “has its roots in the Biblical covenants” as can be expected since much of end times prophecy revolves around Israel. Israel has made several covenants with God (Gen 12:1-3; 13:14-18; 15:1-21; 2 Sam. 7:12-16) which promises Israel a land, a people, and a descendent from king David to continue on the throne ruling over Israel for eternity. These covenants were made with the God who fulfills promises and Israel can be assured that He will keep these promises. And when Israel received her full blessing the entire world will be blessed (Rom. 11:15).
Chafer, Lewis Sperry, Systematic Theology, Originally Published: Dallas, Tex. : Dallas Seminary Press, 1947-1948. (Grand Rapids, MI: Kregel Publications, 1993).
Cone. Christopher, Prolegomena; Introductory Notes on Bible Study & Theological Method, (Ft. Worth, Tyndale Theological Press, 2007).
Enns, Paul P., The Moody Handbook of Theology (Chicago, Ill.: Moody Press, 1997, c1989).
Erickson, Millard J., Christian Theology, 2nd ed. (Grand Rapids, Mich.: Baker Book House, 1998).
Hodge, Charles, Systematic Theology, Originally Published 1872. (Oak Harbor, WA: Logos Research Systems, Inc., 1997).
Ryrie, Charles Caldwell, Basic Theology : A Popular Systemic Guide to Understanding Biblical Truth (Chicago, Ill.: Moody Press, 1999).
Paul P. Enns, The Moody Handbook of Theology (Chicago, Ill.: Moody Press, 1997, c1989), 147.
Millard J. Erickson, Christian Theology, 2nd ed. (Grand Rapids, Mich.: Baker Book House, 1998), 25.
Charles Hodge, Systematic Theology, Originally Published 1872. (Oak Harbor, WA: Logos Research Systems, Inc., 1997), 1:2.
Lewis Sperry Chafer, Systematic Theology, Originally Published: Dallas, Tex. : Dallas Seminary Press, 1947-1948. (Grand Rapids, MI: Kregel Publications, 1993), 1:15.
Enns, The Moody Handbook, 148.
Chafer, Systematic Theology, 5:3.
Chafer, Systematic Theology, 6:3.
Enns, The Moody Handbook, 249.
Chafer, Systematic Theology, 1:401.
Charles Caldwell Ryrie, Basic Theology : A Popular Systemic Guide to Understanding Biblical Truth (Chicago, Ill.: Moody Press, 1999), 73.
Chafer, Systematic Theology, 2:126.
Hodge, Systematic Theology, 1:32.
 Christopher Cone, Prolegomena; Introductory Notes on Bible Study & Theological Method, (Ft. Worth, Tyndale Theological Press, 2007), 223.