Lord, Who Is It?: The Missional Importance of Our Cross-Centered Authenticity

Brian Mahon - 10/23/2022


Call to worship: Psalm 41

Text: John 13:21-38


Still at table, the ball to crucifixion begins to roll with the betrayal of Judas. Though so long a friend to the Friend of sinners, and hidden among the apostles as one himself, Jesus finally reveals Judas for who and what he truly is: no true disciple of Jesus at all. This tragic reality prompts our humility to ask, 'am I genuine?' It should stir in us a desire to do our all, to make good use of the means of grace, to stay as close as possible to the Word Incarnate, Jesus Christ, and to endure in the grace of the cross, the truth of His Word, the community of His love, and the promise of His preserving mercies. We won't be perfect, Peter. But Christ laid down His life for you. And that is sufficient, both, to forgive you, and also to uphold and develop you all the way to Glory. And as we, the church, then sup at the cross together, becoming a visible demonstration of His love, He and the truth of His Gospel will, at least, be vindicated before the eyes of a world watching for heavenly authenticity. For us, such authenticity is thus mission-critical.

Sermon Outline:

  1. The discovery of an inauthentic disciple of Christ. (13:21-30)
  2. The discovery of authentic(ating) Christian community. (13:31-35)
  3. The discovery of Christ for authenticity's endurance. (13:36-38)


Discussion Questions:

  1. Read John 13:21-38. Psalm 41 gives the biblical backdrop.
  2. In 13:21-30, how is it that the other disciples do not know that Judas is the betrayer of whom Jesus speaks? What can we learn from that about true discipleship, self-examination, and the usefulness of an authentic and authenticating church fellowship? Why do you think Peter goes on to have the beloved disciples ask Jesus for a name? Why doesn't Jesus simply give the name? What's implied in the giving of 'the sop' to Judas, both from the perspective of Jesus' gift and Judas' rejection? Was Judas a real disciple of Jesus? Who was his 'father'? What was the true condition of his soul? From this section, what marks can we derive concerning a true disciple of Jesus?
  3. In 13:31-35, Jesus addresses 'the purified' assembly of His disciples. He prepares them for life without Him. That is a major theme of the section running through chapter 17. After reaffirming the true nature of His cross, what's the first preparatory lesson for the true disciples of Jesus?
  4. We need to be clear on 13:34-35. Many want to make it say something other than what it says. What does it say? What's the commandment? Why is it new? Who is the one another? That is, to whom is Jesus speaking? Does the command embrace the world, or is it more specific? Can an assembly of Christians, a church, be inward and, yet, outward focused? Is there a sense in which we can short-circuit missions by being too outward focused? How, according to Jesus, does emphasizing a culture of cross-centered love in the church support the truth of the Gospel to the world? How should that shape a church's missions strategy, philosophy, emphases, etc.? Good things to think about and discuss together.
  5. In 13:36-38, how does Peter demonstrate 1) how we so often miss the essential command of Christ for other concerns and 2) how we so often go to the bag of our own resources for following Jesus instead of going to Jesus Himself? How does Jesus correct Peter? How does Jesus also secure Peter? Will our endurance with the crucified One (and His people) be owing to our strength, or to Christ's? What then is at the heart of our endurance? Do we regularly look to Christ to hold us fast? Do we thank Him for laying down His life for us so that we might be assured of living to the end for Him?
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