In The Gospel (Part 1 and Part 2), I attempted to summarize “the gospel,” reviewing both God’s saving acts in Jesus Christ and their theological significance. Distinguishing the gospel’s results from the gospel itself also proved important in The Gospel (Part 3).

I now want to explore how the gospel functions in the life of the church. No matter what the church faced, the apostles wove the gospel into the very fabric of the church’s life, ministries, and mission. The gospel never amounted to a “shelved” message for the church. It has ongoing significance. Our entire manner of life must be worthy of it (Phil 1:27), in step with it (Gal 2:14), flowing from it (2 Cor 9:13), and never shifting from the hope found in it (Col 1:23).

Fight Temptations to Shift from the Gospel

Pragmatic marketing schemes will tempt the church with “ensured” results—the promise of greater attendance, rapid growth, higher giving, etc. But wherever the gospel is not central to the spiritual transformation of souls, and even numerical growth, God is not ultimately glorified.[1] God is only glorified in “the ends” when we he is also trusted in “the means” to those ends.

Moreover, our own sinful flesh will be pulled to trust in human wisdom of all sorts—bigger buildings, fancier gadgets, latest fads, cutting-edge technology, popular psychology, etc. But only the wisdom of the cross pleases God and conforms people into Christ-likeness.[2] Still more, the devil seeks to preoccupy us with trivial matters that can gradually become our main focus—foolish controversies, identity politics, opinionated bloggers, fear-mongering, etc. All the while, the gospel drifts further and further to the periphery.[3] But in the fight against the world, the flesh, and the devil, the church must heed Christ’s words never to shift from the hope of the gospel (Col 1:23).

God never intended for the church or anything about the church to become “post-gospel;”[4] rather the church must remain a community characterized by ongoing, comprehensive devotion to the gospel.[5] We meet together as a church to help each other live in the good of the gospel daily. That means motivating each other to follow Jesus with the gospel’s empowering truth(s). We lead each other to drink deeply from the endless fountain of God’s glory in Christ, so that our souls rise with gratitude and run with faith. To this end, the following is an attempt to show Christians how to preach and apply the gospel to ourselves and to others.

A Matter of the Heart

In order to establish the functional centrality of the gospel in the church, we must first learn how the gospel gains a functional centrality in our hearts. The Bible will often refer to our inner-most person as “the heart.” When used in this way, some have adequately described the heart as “the causal core of our personhood” or “the control center for life.”[6] Our thoughts, words, actions/reactions, motivations, etc., all stem from the heart (Prov 4:23; 20:5). Depending on its moral and spiritual condition, the heart determines whether we live in ways that please God or in ways that displease God.

The Heart without God’s Grace in Christ

By its own sinful nature, the heart produces evil intentions (Gen 6:5), hatred toward others (Lev 19:17), an obstinate will to God (Ps 14:1; Rom 2:5; Eph 4:18), wicked motives (Jer 17:6), discouragement (Num 32:7), and unbelief in Christ (Heb 3:12). We can also take idols into our hearts (Ezek 14:1-5). Jesus also taught that “out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. These are what defile a person” (Matt 15:18-19). Evil behavior is the result of a much deeper problem: the heart is morally corrupt on its own. Merely improving yourself with good works and rituals ultimately changes nothing about who we really are before the Lord (Matt 15:1-20). What’s truly needed is a new heart.

Jesus also reveals this need for a new heart in Luke 6:43-45, “For no good tree bears bad fruit, nor again does a bad tree bear good fruit, for each tree is known by its own fruit. For figs are not gathered from thornbushes, nor are grapes picked from a bramble bush. The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks” (Luke 6:43-45). In other words, to bear good fruit or produce behavior that glorifies God, we must have a heart that treasures God.

The New Heart by God’s Grace in Christ

By his grace, God gives the new heart that treasures him. Sometimes God refers to circumcising the heart (Deut 10:16; Jer 4:4; Rom 2:28-29). At other times, God refers to the heart undergoing a spiritual cleansing and rebirth (Ezek 36:25-26; cf. John 3:1-8; Acts 15:9). Another example is God commanding “light” to shine into our moral darkness, giving us the light of the knowledge of the glory of God in the face of Jesus Christ (2 Cor 4:6). Thus, a person truly changes when God gives the heart a new moral disposition that loves and treasures God and seeks to honor him.

We can see this inner change in the way Paul addresses the Christians in Rome: “But thanks be to God, that you who were once slaves of sin have become obedient from the heart to the standard of teaching to which you were committed, and, having been set free from sin, have become slaves of righteousness” (Rom 6:17-18). Two observations. One, Paul thanks God because God causes inward change. Two, true obedience stems from a heart freed from sin’s power and filled with new affection for righteousness.

When transformed by the power of God’s grace and compelled by the Holy Spirit and truth, the heart produces inclinations towards God’s will (Ps 119:36; Eph 6:6), generosity (Exod 35:5, 21; 2 Cor 9:13), love-filled worship (Deut 6:5), thanksgiving (Ps 9:1), gladness (Acts 2:46), conviction for sin (Acts 2:37), service toward others (1 John 3:17), faith in Christ (Rom 10:10), compassion (Col 3:12), refreshment (Phm 7), prayerful dependence on the Father (Gal 4:6), and so much more!

Returning to Jesus’ teaching in Luke 6:43-45, once the root of the tree is good, then the fruit will be good too. The figure below attempts to illustrate these truths about the heart (i.e., the root) and the behaviors it produces (i.e., the fruit).

Two Trees Diagram 1

Each tree represents someone’s true spiritual condition. A bad tree/heart bears bad fruit; a good tree/heart bears good fruit. Both trees illustrate that our behavior stems from the condition of our heart and what it ultimately treasures. Pretentious, dishonoring evil behavior has its roots in evil treasure. Genuine, God-glorifying good behavior has its roots in good treasure. When God changes the heart so that we treasure what’s truly good, good fruit will follow that brings God honor.


Thus, true and lasting change that glorifies God is possible. Indeed, it’s more than possible; it’s promised and procured through the person and work of Jesus.[7] This is good news! When received with repentance and faith, the gospel is God’s power for salvation and transformation (Rom 1:16-17; 2 Cor 3:18). Only through the gospel does God make people who were once slaves of sin obedient from the heart (Rom 1:5; 6:1-17; 16:26). Only by using the gospel does the Spirit open the eyes of our heart to see Jesus’ glory and stir our affections for him over our self-centered idolatry (2 Cor 3:1-18; 1 Thess 1:5-10).

So, the goal in our care for one another is to encourage and admonish one another in the gospel (Col 3:16). God views the church as a people who regularly preach and apply the word to one another.[8] Paul exhorts Christians like so: “Let the word of Christ dwell in you richly, teaching and admonishing one another in all wisdom.” We teach and we admonish in all wisdom. The aim is not mere information transfer, but teaching the word of Christ accompanied with wise admonishments that help each other conform our lives to the word of Christ. We daily connect gospel-truth(s) to the very specifics of our lives, such that by treasuring God’s awesome holiness and judgment as well as his boundless love and grace in Christ, we’re compelled to forsake sin and live in ways fully pleasing to him (Eph 5:10; Col 1:10; Heb 13:21).

To be clear, that doesn’t mean we wait to obey God until all our motives are unmixed and pure. Not only are we incapable of such exhaustive self-knowledge, but God is always worthy of our obedience, even when acting out of duty in the moment. But if we want true and lasting change—if God-glorifying obedience flows from delight (over duty) in who he is and what he has done on our behalf in Christ—then the gospel must move our hearts. What does this look like? I'll try to address that in Part 2.


[1]See Rom 1:1-7 where Paul says that God set him apart for “the gospel of Godto bring about the obedience of faith for the sake of his name among all the nations.” The purpose of God in the gospel is the obedience of faith among all the nations, and honoring God’s name is the ultimate goal (cf. Rom 15:8-9). Marketing schemes rob God of glory because they attempt to fabricate results with means other than the gospel, which does not produce the transformation God desires. Cf. Jesus’ parable of the four soils, especially soil three in Matt 13:22.

[2]In 1 Corinthians 1:10-4:17, the primary criticism Paul has for the Corinthians is that they have begun placing confidence in worldly wisdom instead of the wisdom of the cross.

[3]Cf. Acts 26:18; 2 Cor 4:4-6; Eph 6:12; 1 John 5:19.

[4]Cf. Carson, “What is the Gospel?” 165, who speaks against the tendency to treat [spiritual disciplines] as postgospel disciplines, disciplines divorced from what God has done in Christ Jesus in the gospel of the crucified and resurrected Lord…[In the NT] the gospel is regularly presented not only as truth to be received and believed, but the very power of God to transform…Failure to see this point has huge and deleterious consequences.” One consequence that Carson highlights is as follows: “…if the gospel becomes that by which we slip into the kingdom, but all the business of transformation turns on postgospel disciplines and strategies, then we shall constantly be directing the attention of people away from the gospel, away from the cross and resurrection.”

[5]So, for example, in Romans 12:1-13:7, Paul shows the church how the gospel he proclaimed in the first eleven chapters functions practically in the individual’s relationship with God (Rom 12:1-2), in the saints’ relationship to one another (Rom 12:3-16), and in the church’s relationship to the unbelieving world, even governing authorities (Rom 12:17-13:7).

[6]Paul David Tripp, Getting to the Heart of Parenting Leader’s Guide (Philadelphia: Paul Tripp Ministries, n.d.), 3; Tedd Tripp, Shepherding a Child’s Heart, 2nd ed. (Wapwallopen: Shepherd Press, 1995), 3. Cf. Paul David Tripp, Instruments in the Redeemer’s Hands: People in Need of Change Helping People in Need of Change (Philipsburg: P&R, 2002), 57-94.

[7]Cf. Jer 31:31-33; Ezek 11:19; 36:26-27 with Luke 22:20; 1 Cor 11:25; Heb 9:15.

[8]E.g., Rom 10:17; 2 Cor 5:20; 2 Tim 4:2; Heb 3:13; 10:24-25.