Richard Longenecker and Romans 12:2--"But be transformed"

Yet even more important than this negative injunction for believers in Jesus not to live their lives according to the ways of thinking and the practices of the people of “this present age,” Paul exhorts all his hearers and readers of that day — as well as all of us today who profess to be Christians — as follows: “But be transformed by the renewing of your mind” (ἀλλὰ μεταμορφοῦσθε [the form of the verb here being passive] τῇ ἀνακαινώσει τοῦ νοός). This remarkable “metamorphosis” that Paul speaks of here is not some pattern of external decorum or form of outward expression that believers in Jesus are to accept by way of a makeover of their lives and practices. Rather, it is a complete inner change of thought, will, and desires that Christians are to allow God by means of the ministry of his Holy Spirit to bring about in their lives, resulting in a recognizable external change of actions and conduct. It is a metamorphosis of a person’s inner being such as Paul evidently had in mind earlier in 8:12-13 when he wrote: “Therefore, brothers and sisters, we have an obligation — but it is not to the sinful nature, to live according to it. For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.” It is, in fact, the renewal of a believer’s mind that is brought about by God’s Spirit, as also expressed in such later Pauline passages as Eph 4:23 (Christians are “to be made new” in their thoughts and attitudes); Col 3:10 (the believer’s “new self” is “being renewed [by God’s Holy Spirit] in knowledge in the image of its Creator”); and Titus 3:5 (God has “saved us through the washing of rebirth and renewal by the Holy Spirit”). The result of this inner renewal of the believer’s mind, which is brought about by the work of God’s Spirit, is this: “Then you will be able to test and approve what God’s will is — his good, pleasing, and perfect will.” This statement of result is grammatically introduced by Paul’s use of the preposition εἰς (“into,” “unto”) with the articular infinitive τὸ δοκιμάζειν (“to prove by testing” or “approve”) — with such a use of εἰς with an articular infinitive signaling the idea of purpose or result (literally translated “in order to”).

Quoted From: The Epistle to the Romans: A Commentary on the Greek Text, Richard N. Longenecker, William B. Eerdmans Publishing Company, GRAND RAPIDS, MI.