4 Benefits of Studying Systematic Theology

How Does Systematic Theology Relate to One’s Personal Life?1

Godliness, Christlikeness, and Christian spirituality all describe a Christian becoming more like God. The most powerful way to effect this change is by letting the Word of God dwell in one richly (Col. 3:16). When one embraces Scripture without reservation, it will energetically work God’s will in the believer’s life (1 Thess. 2:13). The process could be basically defined as follows: Christian spirituality involves growing to be like God in character and conduct by personally submitting to the transforming work of God’s Word and God’s Spirit.

Intimacy and Maturity

There is no better way to saturate one’s mind with Scripture than by sitting under expository preaching and studying systematic theology. Both will enhance one’s spiritual maturity. The author of Hebrews rejoiced that Jewish Christians had exhibited the intimacy of childlike faith (Heb. 5:12–13) but deplored their lack of advancement to the maturity of meat. So he exhorted, “Therefore let us leave the elementary doctrine of Christ and go on to maturity” (Heb. 6:1). Paul wrote to the Corinthians with similar disappointment (1 Cor. 3:1–3).

Intimacy deals fundamentally with one’s personal relationship with the Father, Son, and Holy Spirit in godwardness. Maturity is the result of intimacy reflecting God’s abiding, growing presence in Christians in regard to godliness (John 15:1–11). Just as a baby or young child, although not yet mature, can enjoy intimacy with a parent, so should a new Christian with the freshly found Savior. This intimacy fuels the maturing process, whereby a child grows into parental likeness.

Intimacy without maturity results in spiritually infantile behavior instead of spiritually adult responses. In contrast, maturity without intimacy results in a stale, joyless Christianity that can easily deteriorate into legalism and sometimes even a major fall into sin. However, Scripture teaches that when intimacy and maturity complement and feed off each other, the result is a strong, vibrant Christian life. Genuine spirituality, then, must be marked by both intimacy and maturity.

Scripture is essential for growing in spiritual maturity. Jesus, Paul, and James each directly communicated God’s clear and frequent pressing demand for spiritual development in the true believer, providing key words for understanding spiritual maturity. We are to be perfect (Matt. 5:48), to be built up to mature manhood (Eph. 4:11–13), to be presented mature in Christ (Col. 1:28), complete and equipped for every good work (2 Tim. 3:16–17), and lacking in nothing (James 1:2–4).

Essential Christian Doctrine

John MacArthur

Systematizing the robust theology that has served as the foundation for John MacArthur’s well-known preaching ministry, this resource surveys theological topics such as the Bible, the Holy Spirit, salvation, the church, and more.

The quickest way to grasp the essence of maturity is to read about the obedience of such people as Abel, Noah, Abraham, Sarah, Isaac, Jacob, and Joseph in Genesis. But one should not quit there. Sixty-five more books of the Bible contain additional stirring accounts of spiritual maturity. This canonical “hall of faith” serves as the ultimate example of God’s affirmation of intimate faith and mature faithfulness.

Hebrews 11 chronicles spiritual maturity at its best. But notice that an exhortation immediately follows Hebrews 11, calling for the same kind of maturity in those who received the letter (Heb. 12:1–3). That exhortation is accompanied by a warning about the Father’s discipline of those who persist in immaturity (12:4–11). Imperfect earthly parenthood is but a faint reflection of God’s flawlessly consistent response to those who by faith in the Lord Jesus Christ have been born again into God’s family (John 1:12–13).

A saint of old, Epaphras, prayed that the Christians at Colossae would stand perfect and fully assured in all the will of God (Col. 4:12). May God, in similar fashion, commend these compelling biblical truths about spiritual maturity to our stewardship of worship and obedience for his great glory.


Christians have been saved to be holy and to live holy lives (1 Pet. 1:14–16). What does it mean to be holy? Both the Hebrew and Greek words for “to be holy” (which appear about two thousand times in Scripture) basically mean “to be set aside for something special.”

Thus, God is holy in that he sets himself apart from creation, humanity, and all pagan gods by the fact of his deity and sinlessness. That’s why the angels sing of God, “Holy, holy, holy” (Isa. 6:3; Rev. 4:8), and why Scripture declares him to be holy (e.g., Ps. 99:9; Isa. 43:15). Thus, the idea of holiness takes on a spiritual meaning among the people of God based on the holy character of God. For instance, the high priest of God had inscribed across his headpiece “Holy to the Lord” (Ex. 39:30). The high priest was especially set apart by God to intercede on behalf of a sinful nation to a holy God for the forgiveness of their transgressions.

Holiness embodies the very essence of Christianity. The holy Savior has saved sinners to be a holy people (1 Pet. 2:4–10). That’s why one of the most common biblical names for a believer is saint, which simply and wonderfully means “saved and set apart” (Rom. 1:7; 1 Cor. 1:2).

When one considers that a holy God saves, it is no surprise to learn that he gives his Holy Spirit to every believer at salvation. A primary purpose of this gift is to equip believers with the power to live a holy life (1 Thess. 4:7–8; 1 John 3:24; 4:13).

So God wants Christians to share his holiness (Heb. 12:10) and to present themselves as slaves of righteousness, which will result in holiness (Rom. 6:19): “Since we have these promises, beloved, let us cleanse ourselves from every defilement of body and spirit, bringing holiness to completion in the fear of God” (2 Cor. 7:1). Thus the author of Hebrews writes, “Strive for peace with everyone, and for the holiness without which no one will see the Lord” (Heb. 12:14). Holiness is the core of a Christian’s experience.

Spiritual maturity springs out of holiness. Scottish theologian John Brown boils holiness down to a definition that we can all understand and pursue:

Holiness does not consist in mystic speculations, enthusiastic fervours, or uncommanded austerities; it consists in thinking as God thinks, and willing as God wills. God’s mind and will are to be known from his word; and, so far as I really understand and believe God’s word, God’s mind becomes my mind, God’s will becomes my will, and according to the measure of my faith, I become holy.2


Closely connected with holiness is sanctification. In many New Testament uses, the word means “salvation” (Acts 20:32; 1 Cor. 1:2).

Sanctification, or being set apart in salvation, should result in believers being set apart for Christian living. Sanctification not only includes the immediate act and fact of salvation but also involves a progressive or growing experience of greater holiness and less sinfulness. It expresses God’s will and fulfills the purpose of God’s salvation call (1 Thess. 4:3–7). Sanctification includes one’s responsibility to participate in continuing what God’s Spirit began in salvation (2 Tim. 2:21; Rev. 22:11).

Christians are constantly exhorted to pursue in their Christian experience what God has declared to be true of them in salvation. Believers are also promised that what is not now complete, God will ultimately finish in glory (Phil. 2:12–13; 1 Thess. 5:23). These passages express one of the great paradoxes of Scripture: Christians are to become what they already are and one day will be. Such certainty of the Christian’s future is captured in texts like these:

For everyone who calls on the name of the Lord will be saved. (Rom. 10:13)

For the word of the cross is folly to those who are perishing, but to us who are being saved it is the power of God. (1 Cor. 1:18)

Besides this you know the time, that the hour has come for you to wake from sleep. For salvation is nearer to us now than when we first believed. (Rom. 13:11)

Sanctification involves the spiritual process that is pictured by a body growing into adulthood (Heb. 5:11–14) or a tree bearing fruit (Ps. 1:3). Growth is not always easy or uniform; however, it should be the direction of a true Christian’s life.

Several obstacles face the believer in this lifelong pursuit. Christians need to know about these obstacles and stay on guard to avoid them or to correct them if they become a part of one’s thinking:

  1. One may think more highly of self than one ought and not pursue holiness as one should (Rom. 12:3).
  2. One may presume upon salvation and assume that since one is saved, holy living is optional (Rom. 6:1–2).
  3. One may have been erroneously taught about the nature of Christian living and so neglect the lordship of Christ (1 Pet. 3:15).
  4. One may lack the zeal or energy to make holiness a priority (2 Cor. 7:1).
  5. One may think that he or she is saved but not truly be saved and then try to live a holy life in the power of the flesh (Matt. 13:5–7, 20–22).

Nature teaches that growth is normal and to be expected; conversely, a lack of growth should sound an alarm that something is seriously wrong. Scripture teaches this same principle in a spiritual sense. Frequently, Acts reports that the early church grew and expanded (see Acts 2:41; 4:4; 5:14; 6:7; 9:31, 35, 42; 11:21; 14:1, 21; 16:5; 17:12). God also has expectations for individual growth in the Christian’s life. These exhortations of Scripture need to be taken seriously (1 Pet. 2:2; 2 Pet. 3:18).

Spiritual maturity springs out of holiness.

The chief agents for this growth are God’s Word (John 17:17; 1 Pet. 2:2) and God’s Spirit (Eph. 5:15–21). When growth occurs, one can quickly acknowledge God as the cause (1 Cor. 3:6–7; Col. 2:19). The Holy Spirit plays a prominent role in providing a true believer with the assurance of salvation. His assurance connects directly with growth (Rom. 8:16–17; 1 John 3:24).

Having formerly been spiritually dead but now made alive to God, the believer can check his vital signs to substantiate the fact that he is indeed alive, because he walks in the works that God has prepared (Eph. 2:1–10). In order to check one’s spiritual health, here are some of the most important vital signs of a true Christian:

  1. Christian fruit (John 15:8)
  2. Love for God’s people (John 13:35)
  3. Concern for personal holiness (1 Pet. 1:13–21)
  4. Love for God’s Word (1 Pet. 2:2–3)
  5. A desire to obey (John 14:15, 21, 23)
  6. A sense of intimacy with God (Rom. 8:14–17)
  7. Perseverance (Phil. 1:27–28)
  8. Fellowship with God’s people (Heb. 10:24–25)
  9. A desire to glorify God (Matt. 5:13–16)
  10. Witness to Christ’s personal reality (1 Pet. 3:15)

As a result of testing their spiritual vital signs, Christians are not to linger or remain at the childhood level but are to grow up in all things. As this individual maturity or growth occurs, it extends to the building up and growth of the corporate body of Christ (Eph. 4:14–16).

Spirituality involves God’s Spirit taking God’s Word and maturing God’s people through the ministry of God’s servants for the spiritual growth of individual believers, which results in the growth of Christ’s body. This is the ultimate goal of systematic theology—to increasingly think and then act in accord with God’s will as one matures in the Christian faith.


  1. For more on this topic, see Benjamin B. Warfield, “The Religious Life of Theological Students,” in Selected Shorter Writings of Benjamin B. Warfield, ed. John E. Meeter, 2 vols. (Nutley, NJ: Presbyterian & Reformed, 1970), 1:411–25.
  2. John Brown, Expository Discourses on the First Epistle of Peter, 2 vols. (Edinburgh: William Oliphant, 1866), 1:11.
  3. For a more detailed discussion of sanctification, see “Sanctification,” in chap. 7, “Salvation” (p. 342)

This article is adapted from Essential Christian Doctrine: A Handbook on Biblical Truth by John MacArthur.

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