Many Western interpreters of Romans 8:12-17 have tended to stress the security of believers’ salvation, since they have been adopted by God and are led by the Holy Spirit. Eastern Orthodox tradition, by contrast, has tended to insist that one can fail to actualize one’s status as a son by refusing to live obediently to Christ and/or failing to suffer with Christ. Exegetes who follow the New Perspective have tended to share these concerns. Making frequent use of Rom 8:12-17, the Byzantine mystic Symeon the New Theologian insists that through ascetic labor and suffering, one must experience a second, spiritual baptism that actualizes the status confirmed at baptism and that allows intimate experience with God. To be truly a son of God, one must participate in the suffering of Christ and put sinful passions to death. At first glance, Symeon’s interpretation would appear to be the polar opposite of that of Ernst Käsemann, who shares the common Western approach that minimalizes human involvement. Like Symeon, Käsemann addresses the experiential dimensions of Rom 8:12-17. Käsemann, however, emphasizes the Spirit’s role as a veritable form of possession driving the believer in the right direction. Käsemann worried, however, that enthusiasm over spiritual experience actually leads to a neglect of love, and hence Paul’s mention of the necessity of suffering with Christ (Rom 8:17) was meant to temper such enthusiasm. This paper will draw on Eastern Orthodox interpretation (especially Symeon), Ernst Käsemann, and scholars who represent the New Perspective to arrive at an interpretation that strikes a balance between interpretations like those of Käsemann and those of Symeon. The claim that one’s sonship can be lost by failure to cooperate with the Spirit and to participate in the suffering of Christ will be exegetically validated and developed; sonship is actualized only by those who participate in Christ’s death through a fearless struggle with sin and the passions. Nonetheless, drawing on the work of Volker Rabens and others, the paper will maintain that this fearlessness can only be grounded in the secure relationship with God that the Spirit facilitates. The Patristic and Eastern Orthodox account of what happens at baptism will itself be a key interpretive resource for developing an understanding of how Paul affirms the profundity of the believer’s new identity while insisting that it can be lost.