As I was reading the other day I came across James 1:4 which reads similarly to Matthew 5:48. The latter passage is often translated “Be perfect as you Father in heaven is perfect” (ESV), which probably is not the best translation. The word translated “perfect” is τέλειος, which carries the idea of being whole or complete. I recently took a class on Matthew and we had a discussion that for Matthew the word τέλειος is signifying by a whole or complete person, one whose heart matches their outward actions. Our English gloss “perfect” signifies for the reader the highest standard, flawless, and lacking in nothing, which does not match the same connotation that τέλειος gives the original readers.
James 1:4 reads “ἡ δὲ ὑπομονὴ ἔργον τέλειον ἐχέτω, ἵνα ἦτε τέλειοι καὶ ὁλόκληροι ἐν μηδενὶ λειπόμενοι.” (And let steadfastness bring about a complete work so that you may be whole and complete, lacking in nothing [my translation]) The ESV translates τέλειος as “perfect” here also. Is James using τέλειος in the same way Matthew is? I believe he is based on 2 observations:
The καὶ connecting τέλειος and ὁλόκληρος “constrains the connected element to be closely associated with what come before.” In this case the word ὁλόκληρος has a definition of to “being complete and meeting all expectations, with integrity, whole, complete, undamaged, intact, blameless.” James is using both τέλειος and ὁλόκληρος as synonyms showing that the one who endures through trials will become a complete and whole person. When a person faces trials generally their heart will be exposed. If their heart is towards God then trials will bring one closer to him in faith. Their actions will flow from a love towards God and neighbor and in this way they are a whole and complete person. If a person has been doing good deeds with an impure heart then trials will bring about a wholeness to this person as well but in an opposite fashion. The actions of a person with a hard heart will reveal actions that are not in accordance with loving God and neighbor. In this way “A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit” - Matthew 7:18
The other reason is based on a thematic argument from James. According to Richard Bauckham, the book of James centers around this idea of wholeness saying, “the thought of the whole letter is structured as an explication and application of the notion of wholeness.” He goes one to say…
“Wholeness cannot be found simply by accepting whatever one is in all one’s disordered and distracted existence. Wholeness is a goal towards which one can move only in relation to a centre which is already whole and from which one can gain wholeness. This means moving in one direction rather than others. It means rejecting values and behavior which are inconsistent with the goal. It means refusing all the idolatries which dominate and diminish human life in favor of the one love which can truly liberate and include all that is good.”
The one who endures trials in this life will have his heart revealed. He will be either a good tree producing good fruit or a bad tree producing bad fruit. In this way, the person will be τέλειος and ὁλόκληρος, their hearts matching their actions.