Beyond the Book with Dr. Merkle: “United to Christ, Walking in the Spirit”

Union with Christ, Christian unity, and spiritual warfare are just a few of the rich theological themes that dominate the book of Ephesians. In “United to Christ, Walking in the Spirit,” Merkle accessibly traces and explains these and other theological themes within Ephesians. In this Q&A, learn from Merkle about how Ephesians uniquely contributes to biblical theology and how you can benefit from his recent book:

What is the book about?

This book offers an accessible summary of the theology of Ephesians that highlights the work of God (the plan of God the Father, union with Christ, being sealed with Spirit) and the response of the Christian (walking in unity and engaging in spiritual warfare). These responses do not earn a right standing before God but flow from being united to Christ and led by the Spirit. 

Who is the target audience?

Readers who desire to know God and his word beyond that of a brief devotional. As I share in the Introduction, “The goal of this book is to offer an accessible summary of the theology of Ephesians that highlights the work of God through his Son for the believer who is then able to love and enjoy God because of the ongoing work of the Spirit. It is because believers are united to Christ that they can walk in the Spirit. Paul has much to say about the behavior of Christians, but such behavior is always based on first beholding and believing in the promises of God that are given to us through Christ. We love because he first loved us, and we serve because he first served us.” 

What motivated you to write the book?

I was asked by the series editors (Tom Schreiner and Brian Rosner), probably because I wrote the Ephesians volume in the Exegetical Guide to the Greek New Testament series and in the ESV Expository Commentary. Because Ephesians is an amazing book, I could not pass up this opportunity. 

How does the theology of Ephesians uniquely contribute to the theology of the Bible?

The theology found in the book of Ephesians is not unique to Ephesians. The Bible presents a consistent message since it is written, not only by human authors but also by authors who were all inspired by God. Yet, there are many doctrines found in Ephesians that are presented in more detail than they are in any other book of the Bible. Allow me to briefly mention three of them: 

First, union with Christ. That is, by faith in Christ, a believer is united to Christ by the Spirit and, consequently, is granted a vast array of privileges and blessings that Christ gained for us. In Ephesians, Paul refers to a believer being “in Christ” (or an equivalent) about 40 times. 

Second, unity of the Church, including Jew and Gentile. The term “Church” occurs nine times in Ephesians, along with other expressions that refer to the concept of the community of believers. The dividing wall between Jew and Gentile has been torn down, and the two have become one (2:14), thus creating “one new man” (2:15). Those redeemed by Christ are “fellow citizens” and “members of the household of God” (2:19). Together they comprise a unique building or a “holy temple” that has become “a dwelling place of God” (2:21–22). And so believers should be “eager to maintain the unity of the Spirit” (4:3), especially since “there is one body and one Spirit … one Lord, one faith, one baptism, one God and Father of all” (4:4–6). 

Third, spiritual warfare. The book of Ephesians has the longest discussion about spiritual warfare in the New Testament (6:10–20). Living a holy life is not simply about battling against our sinful nature but involves a supernatural battle “against spiritual forces in the heavenly places” (6:12). Because of this reality, believers need to understand who they are in Christ and how Christ’s authority over all rulers, authorities, powers, and dominions will ultimately grant them victory. 

What theological matters in Ephesians are often neglected or misunderstood?

One area that always needs clarification is the relationship between faith and works. Ephesians contains 40 commands (imperatives): things we should do or things we should avoid doing. Interestingly, 39 of the commands occur in the second half of the book (chapters 4–6). Before Paul exhorts believers to live a certain way, he first reminds us of the gospel that saves us and empowers us to live holy lives. This is so important. Being a Christian is not about living a certain way in order to please God but recognizing our complete dependence upon God, including reliance on his strength to overcome sin and temptation. Before we seek to live a certain way, we need to become a new creation in Christ. The gospel message is that we will never achieve God’s favor by our good deeds but that God saves us through Christ’s atonement and then empowers to walk in a manner worthy of our calling. Thus, the imperatives that Paul gives in the second half of the epistle are built upon the indicative truths of the first half. Or, to put it as the apostle John did, “We love because he first loved us” (1 John 4:19). We do not love God in order to be loved by him. Likewise, we do not walk according to his commands in order to receive his favor. Rather, because we receive his grace, forgiveness, and empowerment, we can walk according to his commands. We are not saved by our good works; instead, we are created for good works (2:8–10). 

How does Paul’s teachings on being united with Christ and walking in the Spirit equip readers to serve the Church and fulfill the Great Commission?

The frequency of Paul’s references to our spiritual union demonstrates that this teaching is the webbing the connects Paul’s theological framework. Before we can faithfully serve the Church and fulfill the Great Commission, we need to have a firm grasp of who we are in Christ — in a word, we need to know and affirm the gospel. But for Paul, the reality of the gospel changes individuals and communities. Our union with Christ is both the foundation and fuel for Christian living. It is the foundation because we were spiritually dead, but now that we are in Christ, every spiritual blessing is ours (1:3), including the Holy Spirit himself (1:13; 4:30). But it is also the fuel of Christian living because the old person has been crucified with Christ, and now we are able to “put on the new self, the one created according to God’s likeness in righteousness and purity of the truth” (4:24). Both the ability and desire to walk in the Spirit flows from our union with Christ, which is established by faith. Whether we serve our local church or go across the world to bring the gospel of Jesus to an unreached people, we need the firm foundation of who God is and what he has done in Christ, and we need the fuel of the transforming power of Jesus that will propel us to the ends of the earth. 

How has studying the theology of Ephesians shaped you spiritually?

Ephesians is such an amazing book. It is no wonder that Klyne Snodgrass asserts, “Only the Psalms, the Gospel of John, and Romans have been as significant as Ephesians in shaping the life and thought of Christians” (“Ephesians,” NIV Application Commentary [Grand Rapids: Zondervan, 1996], 17). Harold Hoehner likewise declares, “The Letter to the Ephesians is one of the most influential documents in the Christian church” (“Ephesians: An Exegetical Commentary” [Grand Rapids: Baker, 2002], 1). Knowing that God “works all things according to the counsel of his will” is comforting and reassuring (Eph. 1:11). Knowing that we are united with Christ by faith is heart-warming. Knowing that we can walk according to the Spirit because the Spirit of God indwells us is empowering. Knowing that Christ’s Church is united through the gospel is encouraging. And knowing that we can obtain the victory over our enemy through the spiritual armor that God’s provides is faith-enhancing. 

United to Christ, Walking in the Spirit

Paul wrote Ephesians as instruction and encouragement for the church in Ephesus, and it has continued to influence the church for centuries. This New Testament book specifically focuses on the believer’s union with Christ and our inability to stand before God without the work of Jesus Christ and the Spirit, both of which are still essential today. 

In this addition to the New Testament Theology series, scholar Benjamin Merkle offers an accessible summary of the theology of Ephesians that highlights God’s work in salvation and how Christians should respond. Each chapter focuses on a key theological theme — the plan of God, union with Christ, walking according to the Spirit, unity of the church, and spiritual warfare in the present age — and why it is relevant for the church today.

August 23, 2022

paperback, 144 pages

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