Christ prayed for unity. But what type of unity did He have in mind?

Word-Based Unity

And the glory which thou gavest me I have given them, that they may be one, even as we are one (John 17:22).

This is not unity of the world through compromise and tolerance. Rather, Jesus advocated unity in His Word:

Think not that I am come to send peace on earth: I came not to send peace, but a sword (Matthew 10:34).

Jesus did not condone physical violence, so the sword He had in mind was “the sword of the Spirit, which is the Word of God” (Ephesians 6:17). The spiritual battle to be fought is to be the battle against the devil. The battle is for our salvation.

It is the devil's desire to ensure that we never see heaven. The Bible calls him the father of lies. He is the designer of deception. If we don't understand the Word rightly, we can fall into the devil's snares. He has multiple paths to destruction. Many of the paths look good and safe, otherwise we would never go down them. Satan doesn't care if we go to church or even if we claim to be Christian.

Even Christians can be deceived. There are many Christians who are Christians in name only whose lives belie their declaration and who are as deceived as the one that doesn't know God.

Take heed that no man deceive you...For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect (Matthew 24:4,24).

The Word is our sword against the devil. With it we can be fortified and strengthened to withstand him. When we read the Bible and ask the Holy Spirit to lead us as we read, and have a sincere heart that is willing to be changed by the Word we read, then we are walking in the path that leads towards eternal life. Read some tips on studying the Scriptures

But if the Word is being discarded, ignored, belittled, or undermined, or even if we pick and choose only the things in the Bible we like to read and want the words to say what we want them to say, our defense against the wiles of the devil is jeopardized. With this in mind, we can take a fresh look at Christ’s prayer for unity. Jesus is clearly not praying for world unity but for Word-based unity:

I have manifested thy name unto the men which thou gavest Me out of the world; thine they were, and thou gavest them Me; and they have kept thy word. I pray for them. I pray not for the world, but for them which thou hast given Me, for they are thine. I have given them thy Word, and the world hath hated them because they are not of the world, even as I am not of the world. Sanctify them through thy truth. Thy Word is truth (John 17:6, 9, 14, 17 ).

The Gospel of Jesus Christ is beautifully simple, but it does require that we surrender our hearts to His sanctifying power. There can only be one Jesus and He is the Word made flesh. The true can only be separated from the false on the basis of the Word.

Because the Bible is the key ingredient to true unity, this unity will also produce results that are in line with Biblical truths:

For the grace of God that bringeth salvation hath appeared to all men, Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world; Looking for the blessed hope, and the glorious appearance of our great God and Savior Jesus Christ; Who gave himself for us, that he might redeem us from all iniquity, and purify unto himself a peculiar people, zealous of good works (Titus 2:11-14).

God wants to use His people. But this requires us to do more than believe in Him. We need to earnestly confess our sins and come up to the standard of the Word without compromising to the standards of the world. Let us follow Christ's example.

As we unite in humility and meekness, where there are wrongs these will need to be corrected. While we support and sustain each other, we will be able to deal with the erring in a gentle manner (Ephesians 4:15). God can and will use an obedient community of believers that live up to the light that He has given them—those who keep the commandments of God and hold to the testimony of Jesus (Revelation 12:7).

When God first called Paul to follow Him, He led Him to the Church to be taught. God does not make us figure life and ministry out alone, but wants us all to be involved in a community of believers who love the truth.

True Christian unity is Word-based. Jesus prayed, “I have given them thy word; and the world hath hated them, because they are not of the world, even as I am not of the world…Sanctify them through thy truth: thy word is truth” (John 17:14,17). True unity is not about emotions and reckless inclusion, but is based on the Bible alone, which means that sometimes a Bible only attitude will cause friction. Those that prefer a smorgasbord religion, where they pick and choose beliefs that suit their comfort level or their personal agendas will not want a Sola Scriptura basis. This is often manifested as disdain, mockery, or hatred towards those striving to make their lives in line with what they find in the Word of God.

In light of this, how are we to interpret the drive towards Christian unity in the ecumenical movement and the wider goal of religions culminating in one world religion? Can all religions really be one? If every religion believes whatever they want, that directly affects the existence of truth. They can't all be true, can they? If so, then truth is just an opinion and nothing more.

Read about the Protestant Reformation and Catholic Counter Reformation as they relate to true and counterfeit unity