The final line of this chapter may serve as a summary of the six expansions of Old Testament Law. Pennington argues this is the summary of all of Matthew 5 as well as a segue to the next set of teachings on practice (Sermon, 203). Matthew 5:20 introduced the Jesus’s teaching on keeping the Law by saying “For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.” In 5:48 he goes even further, the true disciple of Jesus mush be perfect.

What does it mean to be perfect? The noun τέλειος (teleios) refers to being complete, mature, or whole. The point is not that the true disciple of Jesus score a perfect 100% on the holiness scale, but rather they become mature in their faith and practice so that the do consider their thoughts as more important than their actions, that they do in fact love their enemies as well as their neighbors.

Pennington devotes a chapter to the meaning of “perfect” in his book on the Sermon on the Mount. There is a serious problem translating τέλειος (teleios) with the modern English word “perfect” since the connotation of the English word has the sense of absolute moral perfection, sinless, or purity. But as Pennington rightly points out, the word teleiosis better translated “whole, complete” or even “virtuous” (Sermon, 70). When the disciple of Jesus tries to be perfect in the sense of completely sinless, they will fail since no one can be actually sinless. By connecting teleios with the concept of shalom in the Old Testament, Pennington argues the true disciples of Jesus will be whole, complete, and mature. In fact, Pennington says the idea of teleios is central to everything Jesus is teaching in the Sermon on the Mount.

For a Jewish person, keeping the Law perfectly was the goal, but no one was capable of fully keeping the Law (especially since “being holy” was far more than a moral state in the Law). The sacrifices covered lapses in holiness, but even with a sacrifice what really mattered was the state one one’s heart. Consider Psalm 51:10. When caught in a heinous sin, David begs the Lord to “create in me a clean heart” and in 51:16-17 he acknowledges God is not pleased with sacrifices, but with a “broken and contrite heart.”

In his six examples drawn from the Law, Jesus said one’s thoughts are as important as one’s actions. Internal anger is more damaging than murder. Internal lust is more damaging than adultery. Who could be considered perfect if our thoughts were exposed for all to see?

For this reason, McKnight argues perfection is not “the rigor of sinlessness” but rather the “rigor of utter devotion” (McKnight, Sermon, 146). The true disciple of Jesus is utterly devoted to God, pursuing righteousness in every way possible.

This is not the way most people think of perfection. A recent episode of the Simpsons the evangelical Christian Ned Flanders was teaching a Sunday School lesson on “how to get to heaven.” Several times he said something like “the only way to heaven is to be righteous.” That is not the case at all! The only way to get to heaven is to be forgiven. This is not a license to sin (Romans 6:1-4), but rather the freedom to grow in maturity, the freedom to embrace our wholeness in Christ.

How does this view of perfection as wholeness or maturity change the way the follower of Jesus lives out their life? It ought to relieve the disciple of Jesus from the guilt associated with failure to live up to perfection, but are there some other positive contributions to living out one’s faith?