Here’s a fact many miss: To a very large degree, the unity Christ prayed for does exist among genuine believers, and it is a unity that transcends denominational lines.

All Christians are “in Christ”; therefore they are all one with the Father, and one with each other as well. Notice carefully what Christ says in John 17:22-23: “[I pray] that they may be one, just as We are one; I in them and You in Me, that they may be perfected in unity.” The basis of that unity is not a denominational affiliation; it is our position in Christ.

Faithful evangelical Protestants believe God is answering that prayer of Christ even now. We enjoy an amazing degree of unity with one another, despite our denominational distinctions. In other words, the kind of spiritual unity Christ prayed for does exist in the true body of Christ worldwide despite denominational barriers. Our Lord’s prayer for His church has not gone unanswered.

Christ’s true church is not confined to a single congregation, denomination, or earthly organization. The church is composed of all true believers in Christ, regardless of denominational affiliation or membership in any earthly assembly. In the words of the Westminster Confession of Faith, “The catholic or universal church, which is invisible, consists of the whole number of the elect, that have been, are, or shall be gathered into one, under Christ the Head thereof; and is the spouse, the body, the fullness of him that filleth all in all” (25.1). When the Confession speaks of the church as “invisible,” it does not mean the church is inconspicuous or utterly hidden from view. It means that its precise boundaries cannot be detected through human perception. There are people who claim to be, and appear to be, part of the body, but they are not. Others, perhaps unknown to us, are true believers and members of the body. The exact boundaries of the true church are not always easy to discern. But nonetheless genuine believers are “all one in Christ Jesus” (Galatians 3:28)—united with Him, and therefore united with one another. “For even as the body is one and yet has many members, and all the members of the body, though they are many, are one body, so also is Christ. For by one Spirit we were all baptized into one body” (1 Corinthians 12:12-13).

During His earthly ministry, Christ told the disciples: “I have other sheep, which are not of this fold; I must bring them also, and they will hear My voice; and they will become one flock with one shepherd” (John 10:16). The “one shepherd” is Christ himself, not an earthly vicar. And the “one flock” is also a spiritual reality even now, with believing Jews and Gentiles united in one new body, and the middle wall of partition between Jew and Gentile having been broken down (Ephesians 2:14-16). The perfect manifestation of that unity awaits fulfillment in a future time, when “we all attain to the unity of the faith, and of the knowledge of the Son of God, to a mature man, to the measure of the stature which belongs to the fullness of Christ” (Ephesians 4:13). In the meantime, to settle for the superficial unity imposed by a monstrous worldwide ecclesiastical hierarchy would be a serious mistake.

The unity Christ prayed for has always existed in the true body of Christ. It is an organic, not an organizational unity. It is a spiritual, not a corporeal unity. And it is not a unity without diversity. (If He had wanted unity with no diversity, He would not have gifted us with different spiritual gifts.) But the kind of unity Christ prays for is a unity in spite of our great diversity.

The truth is that on the vital issues there is far more agreement among Protestants than Catholic and Eastern Orthodox church leaders would like to admit. All evangelical Protestants are in agreement on the doctrine of justification by faith (sola fide) and the authority of Scripture (sola Scriptura).

Proof that unity is the rule among believers despite their denominational differences can be seen in a survey of the denominational backgrounds of the men who have contributed to this book. We may not always agree on every point and every particular of secondary doctrinal questions. But on the essential gospel truths we are in full agreement. And our unity in Christ is unbroken by denominational lines between us. We embrace one another with sincere love as members of the one body of Christ. We are one in Christ.

The evangelical school where I studied is an interdenominational Bible institute. My professors were Presbyterians, Baptists, Congregationalists, and Independents. Students came from an incredibly diverse array of Protestant denominations. We prayed together, studied together, and did evangelistic work together. Our denominational differences were no barrier to our unity in Christ.

The church I’m a member of now is a non-denominational church. Our members come from backgrounds as varied as Baptist, Brethren, and Presbyterian congregations. Our pastor is regularly asked to speak in all kinds of denominational settings. In recent years he has spoken in Anglican churches, Baptist conventions, Presbyterian conferences, and charismatic congregations. We do enjoy a tremendous unity with all those who truly love Christ and are faithful to his word—regardless of our denominational differences.

The limits on this trans-denominational unity are set by Scripture itself. We cannot welcome into our circle of fellowship people who deny truths that are essential to the gospel (2 John 7-11); and we cannot embrace people who affirm a gospel Scripture condemns (Galatians 1:18-19). The gospel and all truths essential to it are therefore nonnegotiable points of doctrine, and unity on these matters is a prerequisite to any other kind of unity.

But there’s nothing inherently sinful with holding denominational convictions on secondary issues. Denominations in and of themselves are not necessarily an obstacle to true Christian unity, and Protestants should not be bullied into conceding otherwise.

Of course, when differences on secondary issues are magnified and used to promote strife and hostility between brothers and sisters in Christ, that is sectarianism. It’s the very attitude Paul condemned in Corinth when some of the believers there were dividing in groups loyal to Paul, or Apollos, or Cephas, and refusing fellowship to members of the competing groups. Such sectarianism is certainly sinfully divisive. But that is not a necessary result of denominationalism. And those of us with broad denominational associations and close friendships in Christ across denominational boundaries are living proof of that.

There is room for brethren to disagree within the bonds of unity, and sometimes those disagreements can be sharp (cf. Acts 15:36-39). In fact, it is unlikely that there are any two Christians anywhere who will agree completely on the meaning of every passage of Scripture. Unity does not mean that we must agree up front on every point of truth. But unity certainly does not mean that we should ignore the issue of truth altogether and settle for a superficial organizational unity.