Rarely does one come across the phrase or idea of “internal apologetics” in the literature on the topic of defending the faith.1 It is a subject that is clearly missing in action. That is highly unfortunate, because I contend that the Old Testament and the New Testament speak to internal apologetics more than any
other kind of apologetics. All Christian apologists would agree that basic to the task of apologetics is defending the faith—defending and guarding biblical truth. But virtually all the popular books on apologetics books focus on defending the faith against the un-churched—against atheists, agnostics, skeptics, cultists, evolutionists, humanists, the irreligious anti-Christian, anti-Bible people of the world.
Taylor is representative of the traditional apologists’ view here: “Christian apologetics” is for “critics, seekers, and doubters.”2 That is not the focus of apologetics work in the New Testament. Rather, internal apologetics is dominant. Internal apologetics is the deliberate call of the church, and church leaders in particular, to safeguard biblical doctrine within the confines of the professing church. External apologetics is defending and advancing biblical truth in the world to unbelievers. Consider the following reflection on Acts 20 as illustrative of this principle.
The Model of Acts 20
First Peter 3:15 is an important verse about apologetics. But it is not the only verse about apologetics. In fact, it is not even the primary text about biblical apologetics—it’s just one of dozens of verses on the topic. If we had to pick a paradigmatic New Testament text on defending the faith, that addresses internal as well as external, proactive and defensive—truly comprehensive biblical apologetics—then Acts chapter twenty is a prime candidate. The pertinent portion of the chapter reads as follows:
From Miletus he [Paul] sent to Ephesus and called to him the elders of the church. And when they had come to him, he said to them…“I did not shrink from…solemnly testifying to both Jews and Greeks of repentance toward God and faith in our Lord Jesus Christ…I do not consider my life of any account as dear to myself, so that I may finish my course and the ministry which I received from the Lord Jesus, to testify solemnly of the gospel of the grace of God….I went about preaching the kingdom….Be on guard for yourselves and for all the flock, among which the Holy Spirit has made you overseers, to shepherd the church of God which He purchased with His own blood. I know that after my departure savage wolves will come in among you, not sparing the flock; and from among your own selves men will arise, speaking perverse things, to draw away the disciples after them. Therefore be on the alert, remembering that night and day for a period of three years I did not cease to admonish each one with tears” (20:17-18, 20-21, 24-25, 28-31).
If there ever was an exemplar of Christian apologetics, it was the apostle Paul. This passage is the quintessential apologetics practicum, as it is charged with timeless, prioritized principles for defending the faith issued by Paul to fellow leaders in the church of Ephesus.
First of all, Acts 20 is clearly apologetical in nature. Its tenor is inherently defensive and protective. Paul commands the elders to “be on guard” (20:28), to “be on the alert” (20:31) and to “admonish” or “warn” (20:31). These phrases constitute the nomenclature of apologetics. The elders, or pastors, of the church are called to carry out apologetics as a life’s calling. They are God’s “overseers” (20:28). They are to protect, defend, watch out for and guard the community of faith and its doctrine on God’s behalf.
The second point to consider is what the elders guard. They are to guard the sheep—the people of God. They are to be on guard “for all the flock” (20:28). According to Paul that is priority number one. The work of apologetics is first and foremost “internal,” safeguarding the church, the people of God, the
precious Bride of Christ “which He purchased with His own blood” (20:28). This is true all throughout the New Testament.
Third, this passage makes it clear that the work of apologetics is inseparable from the proclamation of divine revelation and the contents of the gospel in particular. The munitions in Paul’s apologetical arsenal included preaching “repentance toward God and faith in our Lord Jesus Christ” (20:21), declaring “the gospel of the grace of God” (20:24), and “preaching the kingdom” (20:25). This is all special revelation focused on the person and the work of Jesus Christ as found in the gospel. There is no deferring to natural theology here. Trying to prove the plausibility of God’s existence has no place here. Theoretical, non-specific, inane musings are non-existent. Paul knew that “the power of God for
salvation” (Rom 1:16) was found only in heavenly gospel truths. Apologetics is inextricably gospel-oriented and gospel-driven. Defending the faith and evangelism are inextricably linked.
Fourth, in Acts 20 religious people are the target-group for internal apologetics, not unchurched atheists and agnostics. Paul calls the elders to protect the sheep from “savage wolves” (20:29). Savage wolves are spiritual and religious false teachers. They are typified by “speaking perverse things,” seeking to make “disciples after them” (20:30). These rogue spiritual carnivores were religious theists, not atheistic humanists and skeptics.
Traditional Christian philosophers say in unison that the antagonists in the apologetics task are the irreligious, the atheists, the agnostics and the skeptics. Not so for Paul and the rest of the apostles. The greatest threat of attacks on the Church, of false teaching, of distortions of truth, and of insipid worldviews that need to be countered come from religious teachers who masquerade as “Christians” and “Bible teachers,” professing to believe in Jesus. That’s why Jesus gave the apologetical clarion call when He warned, “Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves” (Matt 7:15). Here we see that Paul was simply following Jesus’ example of making a priority of internal apologetics.
And fifth, Acts 20 shows internal apologetics takes place within the church, not in the world! Paul warns, “after my departure savage wolves will come in among you, not sparing the flock” (20:29). Like a virus in the bloodstream, so the most dangerous enemies of Christ will be in the church. Like cancer camouflaging as true bodily organs, so the most imminent spiritual threat to believers is in the Body of Christ. Hymenaeus and Philetus were two such churchmen, who were wolves in sheep’s clothing and their false teaching “spread like gangrene…men who have gone astray from the truth saying that the resurrection has already taken place, and they upset the faith” (2 Tim 2:17- 18). Like weeds choking and strangling the wheat, so truth is undermined most subtly among the saints. Apologetics must begin in the church. The pressing, impending threat is not first outside the church from the Mormons, Muslims or Moonies but from the specious church professors, priests and prophets amidst the people of God.
The Apologists of the Early Church
Church historian John Hannah poignantly highlights the forgotten reality that the earliest “apologists” practiced internal apologetics as a priority and in a normative fashion: “The Apologists were those men and writings that directed and defended the church during the period when it began to come under attack from persecutors on the outside and heretics on the inside.”3 Modern day Christian apologetics has all but forgotten to guard against “heretics on the inside.” Hannah goes on to identify the aberrant groups inside the church that the apologists took on: the Marcionites and the Montanists.4 That would be akin to the true church today taking on and exposing liberal theology, Higher Critical hermeneutics, Darwinian/evolutionary metaphysics, pragmatism, and wayward charismatic theology, threatening movements that are inside the church.
Conclusion
In the 1860’s James Strong poignantly recognized the need for internal apologetics when he wrote the following:
The chief task of the apologist for Christianity in the present age (apart from the metaphysical conflict with Pantheism and Positivism…) is to vindicate the authenticity and the early date of the books of the N. T. against the assaults not merely of avowed skeptics, but also of theologians within the Christian Church….5
Regarding internal apologetics, Paul goes even further, warning the elders that not only will false religious teachers creep into the church from the outside, but also many will actually be indigenous to the church, swelling up from within. He writes, “and from among your own selves men will arise” (Acts 20:30) propagating poisoned, quasi-Christian truth, numbing the intellectual and spiritual sensibilities of people in the church. The elders must be on guard and protect against such assaults on the faith that emanate from the compromised clergy. This is internal apologetics. This is a first-order responsibility of true church leadership.
NOTES
1Stackhouse mentions the phrase once in his book but does not mean the same thing by it that I do in this chapter; John G. Stackhouse, Jr., Humble Apologetics: Defending the Faith Today (New York, NY: Oxford University Press, 2002), 118. Despite his Arminian and rationalistic approach to external apologetics, Norman Geisler is to be commended for his life-long commitment to internal apologetics, as he has exposed errant teaching in the Church and unmasked wayward professing Christians like few have done in our generation. Especially helpful has been his work with inerrancy for half a century in relation to liberalism, postmodernism, Open Theism, higher criticism and countless other “-isms” that certain scoundrels have tried to smuggle into the Church.
2James E. Taylor, Introducing Apologetics: Cultivating Christian Commitment (Grand Rapids, MI: Baker Academic, 2006), 76.
3John Hannah, Our Legacy: The History of Christian Doctrine (Colorado Springs, CO: NavPress, 2001), 40.
4Hannah, Our Legacy, 141.
5John McClintock and James Strong, “Evidences of Christianity” in Cyclopedia of Biblical, Theological and Ecclesiastical Literature, vol. III (Grand Rapids: Baker, 1981), 380. One of the greatest practical benefits of “internal apologetics” is the purity of the Church.
This article was adapted from Cliff McManis’s book, Redeeming Apologetics: Restoring Biblical Supremacy in Defending the Christian Faith (Cupertino, CA: With All Wisdom, 2025). You may read a PDF version of this book here. You may purchase a physical copy here.
