Therefore you shall be perfect, just as your Father in heaven is perfect. (Matthew 5:48)
Therefore. A deduction from the principle laid down in verses 44-47. From the consideration of the example of your Father, and of the insufficiency of being like publicans and heathen. Perfect (τέλειοι). In the Gospels here and Matthew 19:21 only. The word denotes those who have attained the full development of innate powers, in contrast to those who are still in the undeveloped state—adults in contrast to children. Thus the thought here is—Ye shall be satisfied with, and shall attain to, no lower state than that of maturity. But what is it as to which they shall be mature? Surely not the whole Law as illustrated by all the examples since Matthew 19:21; for verses 31, 32 are excluded by the comparison with God immediately following. It must be the subject with which the sentence is closely connected, verses 44-47 (cf. Meyer); love to others even though they have done you wrong. In this respect, viz. love to others, you shall admit, says our Lord, no lower ideal than that of’ maturity, even such maturity as is found in him who sends sun and rain on all alike. Some have seen in this a merely relative maturity, itself capable of further development; but the subject rather demands absolute and final maturity. This does not imply that man will ever have such fullness of love as the Father has, but that he will fully and completely attain to that measure of love to which he as a created being was intended to attain. It may, however, be in accordance with true exegesis to see, with Weiss, for such apparently is his meaning, also an indication of further teaching—the nature of the revelation made known by Christ. For whereas “the fundamental commandment” of the Old Testament, “Ye shall be holy; for I am holy” (Le 11:44, 45), was the more negative thought of God’s exaltation above the impurity of created beings, our Lord now puts forth “the positive conception of the Divine perfection, whose nature is all-embracing, self-sacrificing love. And in place of the God, forever separated from his polluted people by his holiness, to whom they can only render themselves worthy of approach through the most anxious abstinence from all impurity, and by means of the statutes for purification contained in the Law, there is on the ground of this new revelation the Father in heaven, who stoops to his children in love, and so operates that they must and can be like him” (Weiss, ‘Life,’ 2.156). The simple and straightforward meaning of the verse, however, is this—You shall take no lower standard in love to enemies than God shows to those who ill treat him, and you shall, in fact, attain to this standard. Upon this (for the limitation of the meaning to one point makes no real difference) there arises the question which has been of so much importance in all ages of the Church—what is the measure of attainment that is really possible for Christ’s disciples upon earth? Ought they not to expect to live perfect lives? But the text gives no warrant for such an assertion. No doubt it says that attainment to maturity—to perfection according to creaturely limits —is eventually possible. That is implied in ἔσεσθε (vide supra). But when this attainment can be made is not stated. Many will, indeed, affirm that, as our Lord is giving directions to his disciples concerning things in this life, the attainment also is affirmed to be possible in this life. But this by no means follows. Christ gives the command, and by the form of it implies that it shall be carried out to the full. But this is quite consistent with the conception of a gradually increasing development of love which, in fact will attain maturity, a state in which God’s love has ever been; but not immediately and not before the final completion of all Christ’s work in us. The words form, indeed, a promise as well as a command, but the absence of a statement of time forbids us to claim the verse as a warrant for asserting that the τελειότης referred to can be attained in this life. Trench (’Syr.,’ § 22.) explains the passage by saying that the adjective is used the first time in a relative, and the second time in an absolute, sense. But this does not seem as probable as the interpretation given above, according to which the adjective is in both cases used absolutely. His following words, however, deserve careful attention. “The Christian shall be ‘perfect,’ yet not in the sense in which some of the sects preach the doctrine of perfection, who, so soon as their words are looked into, are found either to mean nothing which they could not have expressed by a word less liable to misunderstanding; or to mean something which no man in this life shall attain, and which he who affirms he has attained is deceiving himself, or others, or both.” Even as your Father which is in heaven is perfect; Revised Version, as your heavenly Father is perfect; so the manuscripts. Observe again not “the Father” but your Father; nerving them to fulfil the summons to likeness to him (cf. verse 16).