While theological anthropology is emphasized throughout the Pauline corpus, Ephesians is noteworthy for its repeated deployment of images involving human development. In Ephesians, the multi-ethnic church is portrayed as a “new human” (2:15) and a “body” (2:16; 4:4, 12, 16; 5:23, 30), which is undergoing tremendous growth until it attains “mature manhood” and possesses “the stature of the fullness of Christ” (4:13-16). In the meantime, individual believers are called to advance beyond spiritual infancy (4:14) now that they have “learned Christ,” have taken off “the old human,” and have “put on the new human” (4:20-24), which “renews” their minds and adorns them with Spirit-wrought virtues (4:25-5:21) and protective divine weaponry (6:10-18). The soteriological and ecclesial significance of these terms and texts has long been appreciated. Lacking, however, is a scholarly attempt to assemble these discreet images into a coherent portrait of Christian maturation. Yet a clearer picture begins to emerge once it is realized that this collage of metaphors draws upon ancient conceptions of human development. While Paul’s contemporaries used an array of terms to construct their varied and nuanced versions of the human lifecycle, there nonetheless existed within the Greco-Roman world a basic shared understanding of the continuums according to which the average male and average female advanced from one life stage to another. For example, all males began life as an infant/child and ended life as an old man, the latter stage often beginning in the late forties or fifties. Further, the end of childhood and the beginning of adulthood occurred in the mid-teens, as determined by the male’s father or guardian. This moment of coming-of-age was symbolized through the removal of the child’s toga praetexta and its replacement with the toga virilis—representing the boy’s attainment of citizenship, his right to join the army, and his right to marry. Despite having officially reached adulthood, however, full maturity (ὁ τέλειος ἀνήρ) was not considered to have been attained until 25-30 years of age, when the man had grown facial hair, had developed muscle tone, and had ridden himself of the vices inherent to youth (ὁ νεανίας). Only at this time was the man admitted to the senate and eligible for public office. Nearly all these developmental milestones are represented in some fashion within Paul’s discourse in Ephesians and can be arranged to form a coherent theology of Christian maturation. This paper will reconstruct Ephesians’ implied lifecycle continuum, arguing that Paul deployed key developmental terminology within the letter in order to show that new life in Christ marks the believer’s transition from an existence defined by infancy to that which signifies initial (though not final) adulthood—a liminal stage that implies one’s right to engage in spiritual combat as well as one’s need to continue advancing towards full maturity.