“You must be perfect”, Jesus instructs (Matt 5:48). Or, in the version Luke reports, “you must be merciful” (Luke 6:36). Whatever versions you prefer, both of them cite, as the model to be followed and aspired towards, “your Father” (meaning, of course, God).
How can we aspire to be precisely as God is? Well, that’s what Jesus instructs his earliest followers (and through them, us, today). So, what is God like? Perfect? Or Merciful?
Jesus, according to the tradition reflected in the Gospels, chose a group of his followers to form a core group of inner disciples (Luke 6:1–4; compare Mark 3:14–19, Matt 10:1–4, and Acts 1:23–14; and see also the reference to “the twelve”, unnamed, in John 6:66–71).
Admittedly, those named are all males (although the precise names vary a little between the various listings), which in itself contradicts the clear indication that women were at the very centre of those who followed Jesus from the start (Mark 15:40–41; Matt 27:55–56; Luke 23:49) and, indeed, that a group of women provided material support for Jesus from early on (Luke 8:1–3). But in a strongly patriarchal context, what else (sigh) might we expect?
It was, perhaps, to this inner group that Jesus spoke—although the setting for the teaching provided in Matt 5:48 is simply “his disciples” atop the mountain (Matt 5:1). “The twelve” were yet to be identified by name in Matthew; and besides, by the end of this lengthy discourse of teachings which Matthew has collated together (and which we now call The Sermon on the Mount), “the crowds” had gathered, listening in; for Matthew affirms that “the crowds were astounded at his teaching” (Matt 7:28).
That’s the setting for the admonition to “be perfect”. Jesus seems to be advocating that his inner group of followers demonstrate their scrupulous adherence to the Jewish Torah—indeed, he has advocated this a little earlier (at 5:17–20), with the implication (as we read this in English) that he is seeking absolutely perfect adherence to every single tiny detail of the Torah. That’s a large demand!
However, the basic sense of the word translated as “perfect” (teleios) is not so much scrupulous adherence to minute details, but rather that of moving to a state of fulfilment, completion, or wholeness. It is used five times in Matthew’s book of origins to indicate that Jesus has completed a discrete section of teaching (Matt 7:28; 11:1; 13:53; 19:1; 26:1). It is used in other Gospels to signal ways in which Jesus brings scriptural texts to fulfilment (Luke 18:31; 22:37; John 19:28; and see Luke 1:45).
In Matthew’s narrative, it even has the sense of the present age coming to an end (Matt 10:22; 24:6, 14)—a completion, or fulfilment, not simply in the ending of the present age, but in the ushering in of the new age. That may well be the force intended by the authorities of the fourth Gospel, when the dying Jesus utters the phrase tetelestai, “it is finished”, or better, “it is now fully accomplished” (John 19:30).
Perhaps its most controversial occurrence is at Rom 10:4, where Paul indicates that Christ is the telos of the law: does this infer “end as as abolition” (an unsatisfactory supercessionist reading), or (as I prefer) “end as in bringing to the height of fulfilment”? This accords with the use of the term in Pauline texts, where teleioi is used to refer to those with spiritual maturity (1 Cor 14:20; Phil 3:12, 15; Col 1:28; Eph 4:13). It is perhaps similar to the meaning in Hebrews, in the claim that Jesus is the means of offering a perfect sacrifice (Heb 2:10; 5:9) through which we are perfected (teteleiōken, Heb 10:14).
Thus, by using this rich theological term at 5:48, Matthew has Jesus indicate that those who follow him should be oriented towards being wholly and completely fulfilled as his followers, in the way that God is complete and whole in God’s own being.
Indeed, the clearest indication of what this state would look like, for his followers, is given in the conversation that Jesus later has with a young man who claims that he has, most assuredly, kept the commandments (19:16–20). What more does he need to do? he wonders. Jesus replies, “If you wish to be perfect, go, sell your possessions, and give the money to the poor, and you will have treasure in heaven; then come, follow me” (19:21). Understandably, we are told that “when the young man heard this word, he went away grieving, for he had many possessions” (19:22).
If you would like to follow up in detail the range of meaning and nuances involved in understanding the Greek word teleios (and related terms) used here, you will find a good discussion at https://www.godwhospeaks.org/post/teleios-τέλειος-7th-sunday-in-ordinary-time-a
In Luke’s orderly account, by contrast, Jesus delivers his instruction to “be merciful” on “a level place”, amidst a crowd of people “from all Judea, Jerusalem, and the coast of Tyre and Sidon” (6:17) who are desperately seeking some measure of that mercy from Jesus himself, as they “were trying to touch him, for power came out from him and healed all of them” (6:19).
The time that Jesus had recently spent on top of a mountain in Luke’s narrative had been personal, perhaps even private, devoted to all-night prayer (Luke 6:12) and the designation of those twelve disciples “whom he also named apostles” (6:13). These teachings, “on a level place”, were given amidst the curiosity and noise and anxious pressings to be healed of “a great multitude … all trying to touch him” (6:17, 19).
Jesus confronts this crowd with a series of provocative instructions in a section known as the sermon on the plain. After asserting that God blesses the poor, those who hunger and grieve, and brings woe upon the rich, those who are filled with food and laughter (6:20–26), he goes on to instruct them, not just to “love your neighbour” (as he later states, at 10:27, clearly drawing on Lev 19:18), but more than that, to “love your enemies” (6:27, 35).
Luke’s account stands in contrast to his teaching in the Gospel we attribute to Matthew, where Jesus exhorts his disciples to “be perfect, as your father in heaven is perfect” (Matt 5:48). The instruction to keep every one of “the least of these commandments”, following every letter, indeed every stroke of every letter (5:18–19) is completely absent in Luke’s narrative. (The isolated saying of Luke 16:16–17 perhaps comes close to this perspective.)
By contrast, the Lukan account has Jesus instructing the crowds to “be merciful, just as your father is merciful” (Luke 6:36, in the NRSV translation). What does he mean by this instruction? I believe that he wants the crowds to “show deep, empathic compassion, just as your father shows this deep, empathic compassion” (my own translation). For the Greek word employed at 6:36 is an unusual word.
The Lukan Jesus does not use the regular word for “mercy”, eleos, which appears 26 times in the New Testament (along with 29 occurrences of its cognate verb, eleeō). This is the usual NT translation for the Hebrew word for “mercy” (see Matt 9:13, quoting Hosea 6:6). It’s a word that has a sense of care for the other, as reflected in the Torah provisions of Lev 19:33-34, for instance.
Here, the word is oiktirmōn, a word which is rare in the NT but used regularly in the Septuagint to translate that quality of God which demonstrates deep, compassionate, empathic concern for the other. And this quality of relating in a way that attempts to “get right inside the skin” of the other person, is to behave in a way that is entirely and thoroughly counter-cultural.
People in the first century Mediterranean world were governed by the cultural patterns of patron-client relationships, where benefaction by the greater to the lesser was balanced by obligations that the lesser had towards the greater. Jesus assumes this way of operating in a number of his parables and teachings (such as Matt 18:23–35; Luke 11:11–12; 14:12; 19:11–27); it was the common cultural practice of ancient society (see a helpful discussion of this system at https://biblicalstudies.org.uk/pdf/ashland_theological_journal/31-1_032.pdf).
But not here, in the Lukan account of teachings spoken by Jesus (Luke 6:36). Here, the expectation is for giving without expectation of return. Acting without anticipation of the obligatory response. Compassionate care, offered and given wholly for the sake of the other, not with any expectation of gaining something in response. That is the focus for the Lukan Jesus.
And that is most surely just as deeply penetrating, just as all-consuming, and just as strongly confronting, as the Matthean demand to “be perfect”. Whichever version we prefer, we are facing a momentous challenge!