Nielsen’s Nook

[a] οἰκτιρμῶν is used only a handful of times by Paul in the NT (Rom 12:1; 2 Cor 1:3; Phil 2:1; Col 3:12)  and also Heb 10:28.  It connotes mercy and compassion.  The word occurs frequently in the LXX and Deuterocanonical books. It rarely occurs in the singular [BAGD, 561].

[b] συσχηματίζεσθε is only used twice in the NT (Rom 12:2; 1 Pet 1:14), both times in the negative, and in no other Christian corpus inspired or otherwise of which I am aware.  This notion of not being conformed is always with regard to the sphere of sinfulness (the world outwardly or our own lust inwardly).  It always occurs in juxtaposition with the concept of being transformed into the holiness of God (c.f., 1 Pet 1:15-16).

[c] μεταμορφοῦσθε is of course the word from which we get the English cognate metamorphosis.  However, the use of this word in the NT far transcends the idea of mere change. The NT uses μεταμορφόω with a view towards a very specific eschatological telos.  The word is used of Christ when he is transfigured before Peter, James and John (Matt 17:2; Mark 9:2).  The other two instances of the word in the NT occur in Paul, both describing the holiness of Christ to which his followers are being transformed in union with Him (Rom 12:2; 2 Cor 3:18).  In short, μεταμορφόω would appear to be clearly an extension of the participation in Christ that believers share.

[d] ἀνακαινώσει in the NT describes the Spiritual renewal of a person.  It is used only here in Rom 12:2 and in Titus 3:5.

[e] τέλειον is a word that does not go well into English.  It is usually translated as perfect or complete; however, both of those translations do not capture the purposed and planned aspect of the word.  I.e., the completion in view is one that is the result of everything occurring according to plan.  So I have decided to go with the transliteration.