The final Sunday in Epiphany is when the church remembers the Transfiguration of our Lord. Truth to tell, it's a strange story, told in all three of the Synoptic Gospels (Matthew 17:1-8; Mark 9:2-8; and Luke 9:28-36).
In the story, Jesus takes three of his disciples--Peter, James and John--with him up onto a "high mountain," where his appearance dramatically changes, i.e., he is "transfigured" before them. In Matthew's telling, Jesus' face shines "like the sun," and his garments become "as white as light." After Jesus is joined by Moses and Elijah, a voice comes from heaven--it's God's voice--and says, "This is my beloved son with whom I am well pleased. Listen to him."
The author of 2 Peter appeals to this event in the epistle lesson for today as part of a sustained argument with a group of people to which he refers as "false teachers" (2:1). But before we look at the false teachers, a brief note about the authorship and genre of 2 Peter is in order. This letter appears to be a "testament," i.e., a common genre of Jewish literature in which the purported author is presented as being near death and giving a final message to his people. These final messages usually included ethical exhortation and predictions of things that were to happen in the future. Testaments were pseudepigraphical (written under an assumed name) and probably understood by their readers as exercises in historical imagination in which words are put into the mouth of some now-dead historical figure. As a testament, 2 Peter was probably written a few decades after the death of Peter in order to bring the message of Peter to bear on a situation of false teaching that arose during those decades.1
These false teachers that 2 Peter opposed appear to have been teaching that the belief in the eschatological coming (Parousia) of Jesus Christ was a "cleverly devised myth" (1:16) which it would be good to discard. Their reasoning seems to have been that Jesus' return was expected during the lifetimes of the first Christian generation. Since by their time this generation had died without seeing the Parousia, this expectation must have been false. (See 3:4--"Where is the promise of his coming? For ever since the fathers [probably a reference to Peter's generation] fell asleep, all things have continued as they were from the beginning of creation.") From the perspective of the author of 2 Peter, this abandonment of the expectation of the Parousia (and its related expectation--eschatological judgment) is ethically disastrous. In a passage that is so unreservedly damning that it is almost difficult to read, he criticizes these false teachers for being corrupt and sinful...and worse still, hoodwinking others into joining them in their corruption (2:10b-22).
There is, of course, something to be said for the position of 2 Peter's false teachers. The Lord Jesus has yet to return in glory and power, and insisting on the reality of this expectation can come across as a little embarrassing. Things are as they ever have been! Eschatological expectations can seem woefully out of touch with the realities of this world, where justice is too often left undone and where eschatological hopes look strangely unrealistic. How can intelligent people take the return of Christ seriously? Why not just admit as much and move on?
The author of 2 Peter wants more for his audience than this, however. His appeal to the Transfiguration is an attempt to root the eschatological expectations of the church in the eyewitness (and ear-witness) experience of those who were present at the Transfiguration. They saw Jesus "receive honor and glory from God" that day, and they heard the authoritative voice from heaven: "This is my beloved son, with whom I am well pleased." The Transfiguration is understood as a foretaste of the Parousia, when the Son will come again, in the same glory and honor that infused the Transfigured Jesus, with salvation and judgment.
Still more, 2 Peter maintains that the eschatological hopes of Christians have profound ethical consequences. In other words, the expectation of Christ's return makes (or ought to make) a difference in the day to day lives of those of us who expect it. That difference is in how we live. Our lives ought to be characterized by things such as faith, goodness, knowledge, self-control, endurance, godliness, mutual affection and love (1:5-7). The expectation of eschatological judgment ought to provoke us to lives characterized by godliness and holiness (3:11). This is a far better--one might say more faithful--ethical profile than the one associated with the false teachers (2:10b-22).
As the last Sunday in Epiphany, this is the day when the church turns the corner into Lent, the forty day season of preparation for the death and resurrection of Jesus which we celebrate during Holy Week and Easter. Lent is traditionally a season for grief and repentance, in which Christians look hard at our lives and notice where we come up short of God's expectations for us. The idea for the season is for us to repent of our sin and to work hard to become the sorts of people who are ready to behold the risen Lord. That expectation of the resurrection of the Lord, an eschatological event if ever there was one, is supposed to have ethical consequences for us during the Season of Lent.
2 Peter 1:16-20 grounds the expectation of the eschatological return of our Lord in the experience of Peter, James and John on the Mount of Transfiguration. That expectation is understood as having significant daily behavioral consequences which (ought to) distinguish Christians from an unholy world. Consequently, the passage can serve as a good archway through which to enter Lent.
1 For a fuller discussion of the genre and authorship of 2 Peter, see Richard J. Bauckham, "2 Peter," in Dictionary of the Later New Testament and Its Developments (ed. Ralph P. Martin and Peter H. Davids; Downers Grove, Ill.: InterVarsity Press, 1997), 923-927.