(This is an excerpt from a recent paper I wrote, “The Trinity in the Old Testament: A Present But Elusive Mystery.” It suggests that the development of the Trinity in the Bible follows a mystery-revelation pattern.)
Mystery without mysterion
In his essay entitled “Mystery and Fulfillment” in Justification and Variegated Nomism, vol. 2, D. A. Carson includes a section called “Mystery without mysterion,” where he asserts that the idea of mystery—something hidden now revealed (cf. Matt. 13:10-17, 34-35)—can occur in NT literature in places where the word, mysterion, is not used explicitly. He suggests this to be the case in fourth gospel where “although John never uses the term mysterion he sometimes provides fresh revelation that has clearly been hidden in time past, but which is some how said to be connected to the very Scriptures in which it has been hidden (e.g. John 2:19-22).” From this general description, Carson references Philip Kramer’s 2004 dissertation on the subject, and produces four criteria to evaluate mystery-language: “(1) [the] referent mysterion is the gospel or some part of it; (2) the disclosure of this mystery may be traced, at least in part, to the Christophany Paul experienced on the Damascus Road; (3) the text makes it clear that this mysterion was once hidden but is now revealed; (4) the Old Testament Scriptures constitute the medium in which the mysterion was hidden and by which it is revealed.” This taxonomy fits very well when applied to the Trinity’s development from the Old Testament into the New Testament.
First, as John Piper has proclaimed, “God is the Gospel!” There is no part of the gospel that is not Trinitarian, and each member of the Trinity functions in their unique role to call, atone, and regenerate (cf. Eph. 1:3-14). Moreover, in the Old Testament, the characteristics ascribed to the Father, the Word of God, the Spirit of God, and the coming Messiah are consistent with the Incarnation and Pentecost. In other words, what was foretold through types, shadows, and veiled allusions, is now manifest in Jesus and the Spirit.
Second, the Trinity is defined and explained by the life, death, and resurrection of Christ and the arrival of his Spirit. In fact, without these, the verbal expressions of Father, Son, and Holy Spirit are incomplete, at best. For instance, the union of three persons is most clear in passages like John 14:16-17 where Jesus says, “I will ask the Father, and He will give you another [of the same kind] Helper…the Spirit of Truth” (cf. John 15:26). Though Kramer’s criterion delimits the disclosure of the mystery to Paul’s Damascus road experience, this restriction is too narrow. While it fits his specific subject in Galatians, it should be broadened across the New Testament. It should be remembered, Paul had a Damascus road experience because he was lacking the necessary apostolic ‘credentials’ that all the other disciples received (cf. Mark 3: 13-14; Acts 1:21-22). Consequently, the corroborating NT evidence is not isolated to one man’s encounter with Jesus, it is the composite person and work of Jesus Christ that makes sense of the Old Testament in general, and the Trinity, in particular. In this Augustine was right, “[God’s] grace hid itself under a veil in the Old Testament, but it has been revealed in the New Testament according to the most perfectly ordered dispensation of the ages.” Therefore, recognizing the Trinity in the OT depends upon NT Christology.
Third, the doctrine of the Trinity was hidden in the OT and revealed in the NT. While the component parts were scattered throughout the OT, the necessary historical events (i.e. Incarnation and Pentecost) were lacking to make sense of the mysterious pluralities, theophanies, and eschatological promises. Even into the church age, it took over three centuries to sort out the biblical doctrine of the Trinity and its ontological entailments. Yet, this should not be surprising. It is the natural state of affairs with biblical mysteries. Proverbs 25:2 enlightens us, “It is the glory of God to conceal things, but the glory of kings is to search things out.” Likewise, 1 Corinthians 2:7 says, “We impart a secret and hidden wisdom of God, which God decreed before the ages for our glory.” It is the wisdom and glory of God to hide his Triune nature from those without the Spirit, and to reveal himself to those united to Christ—it should not be forgotten that these are NT realities.
Fourth, New Testament authors consistently appeal to the Old Testament to explain the rise of Trinitarian thought, thus proving the mysterious nature of God’s hiddenness and revelation in the OT. Moreover, traces of the Trinity in the OT are not scant. Rather, the most illustrious Trinitarian passages in the NT are often dependent upon or giving explanation to OT passages (cf. Matt. 28:18-20 –> Dan. 7:13-14; 2 Chronicles 36:22-23; Num. 6:22-26; John 1:1-18 –> Gen. 1:1; Ex. 19-20; 1 Cor. 8:1-6 –> Deut. 6:4). Thus it seems that in God’s wise providence he has revealed his Triune nature perfectly and progressively, and as we study his Scripture we have the blessed privilege of seeing his mystery and revelation, ultimately revealed in and through Jesus Christ (John 1:18; Heb. 1:1-2).
Tomorrow, I will post a reflection on these intertextual considerations. Until then, may we take this Lord’s Day to worship the God the Father, God the Son, and God the Holy Spirit.
Sola Deo Gloria, dss
 D.A. Carson, “Mystery and Fulfillment” in Justification and Varigated Nominianism: The Paradoxes of Paul, vol. 2, ed. D.A. Carson, Peter T. O’Brien, and Mark A. Seifrid (Grand Rapids: Baker Academic, 2004), 424.
 Philip Kramer, “Mystery without mystery in Galatians: An examination of the relationship between revelatory language in Galatians 1:11–17 and scriptural references in Galatians 3:6–18, 4:21–31” Ph.D. diss., Trinity Evangelical Divinity School, 2004
 Carson, “Mystery and Fulfillment,” 425, footnote 91.
 John Piper, God is the Gospel: Meditations on God’s Love as the Gift of Himself (Wheaton: Crossway Books, 2005).
 The requirements outlined by Peter in Acts 1 make more sense in light of this mysterion discussion, that the mysteries of the OT, which foretold the gospel (Gal. 3:8), could only be understood through a comprehensive knowledge of Jesus Christ (cf. Luke 24:25-27, 44-49). This is complicit with Paul’s apostolic ministry which faithfully expounded the OT Scriptures (cf. Acts 17:2).
 Augustine, “A Treatise on the Spirit and the Letter” in Anti-Pelagian Writing, Nicene and Post-Nicene Fathers, American ed., vol. 5 (United States: Christian Literature, 1887; reprint, Peabody, MA: Hendrickson, 2004), 95.
 Alec Motyer puts it this way, “It was Jesus who came from the outside as the incarnate Son of God, Jesus who was raised from the dead as the Son of God with power, who chose to validate the Old Testament in retrospect and the New Testament in prospect, and who is himself the grand theme of the ‘story-line’ of both Testaments, the focal-point giving coherence to the total ‘picture’ in all its complexities” (Look to the Rock: An Old Testament Background to Our Understanding of Christ [Grand Rapids: Kregel, 1996], 22).
 For more on the condition of the believer in the OT, see Jim Hamilton, God’s Indwelling Presence.