He is the perfect Person with the highest authority that God can give. Jesus affirms, “All authority in heaven and on earth has been given to Me” (Matthew 28:18). How much more can God give than “all”? What realm is greater than “heaven and earth”? Based on such power, Jesus orders His followers to “make disciples” (Matthew 28:19). Disciples for whom? Disciples for Jesus who alone has all authority! Whose commands should disciples obey? “… Teaching them to observe all that I [Jesus] have commanded you” (Matthew 28:20).
Such complete and absolute authority settles the issues associated with unity. For example, Paul’s appeal, “that all of you agree” is more literally, “that you all speak the same thing” (1 Corinthians 1:10). Which same thing should they speak? The same thing their one Lord teaches them to speak! The Scriptures teach us His way of speaking. So, in correcting their party spirit, Paul points to “what is written,”
I have applied all these things to myself and Apollos for your benefit, brothers, that you may learn by us not to go beyond what is written, that none of you may be puffed up in favor of one against another (1 Corinthians 4:6).
“Be united in the same mind.”
Paul also says, “be united in the same mind” (1 Corinthians 1:10). Which mind should we share? Should we unite on my ideas or your ideas? Neither. Unite by sharing the “same mind”—the one mind of one Lord! Is that possible? Surely the Lord does not command that which cannot be obeyed. In this same context, Paul shows that the Spirit has revealed the divine will, and he concludes, “We have the mind of Christ” (1 Corinthians 2:16). In a similar context promoting unity, Paul also writes,
Complete my joy by being of the same mind, having the same love, being in full accord and of one mind. … Have this mind among yourselves, which is yours in Christ Jesus (Philippians 2:2, 5).
Paul gives the same instruction to immature Christians at Corinth and to more mature Christians at Philippi. The key to unity is not our relative maturity, whether we are younger in the faith or older. What matters is our direction. Are we committed to following one Lord? Are we learning His mind? Reflecting Ephesians 4:15, are we growing up in every way into Him who is the Head, into Christ? One body has one Head. The spiritual family remains united when led by one Father through His one Son. The kingdom’s unity depends on loyalty to one King. God’s one flock gathers behind His one Shepherd.
[Jesus says,] I am the good Shepherd. I know My own and My own know Me, just as the Father knows Me and I know the Father; and I lay down My life for the sheep. And I have other sheep that are not of this fold. I must bring them also, and they will listen to My voice. So there will be one flock, one Shepherd (John 10:14-16).