The Doctrine of the Trinity and the Means of the Christian Mission
Not only does trinitarian theology shape the goal toward which the Christian mission is striving; it also clarifies the means which are to be used in the pursuit of that goal. Redemption is ultimately an accomplishment of the triune God; he alone is the doer of the work, and therefore, any human activity must flow from his prior activity, and be directed and empowered by him. The mission that God left his people with is ultimately his mission, and advances on the basis of his eternal, immutable design; and so, any human activity which fails to take into account Godâ€™s redemptive plan as he has made it known is bound to be frustrated. Human mission endeavors are likely to be successful only as they understand the divine agenda and lean upon divine strength. This means that a first qualification for any missionary is a knowledge of the triune God; an awareness of the role of the persons of the Godhead in the work of redemption, as revealed in the scriptures; and a heart-attitude of faith in those joint operations of the persons of the Trinity.
For example, take the scriptural revelation of the work of the Father in the plan of redemption: he is the ultimate planner, the source from whom the whole work flows and is governed. We see throughout the gospel of John that the Son, in the fulfillment of his part of the redemptive work, acts in an unceasing obedience to the Fatherâ€™s will (e.g. John 5:17-19, 30; 8:28-29; 10:17-18; 14:31; 17:4). Likewise the Spirit, when he comes, speaks not on his own, but only what he has heard from the Father and the Son (John 14:26; 15:26; 16:13-14). This role of the Father in planning out the work of redemption is seen with special clarity in the aspect of his choosing its subjects. We have already observed that the Father has chosen a specific people to give to the Son, and that the Son has purposed to redeem these alone (e.g. John 6:37-40; 10:29; 17:1-2, 6, 10); we may add to this testimony the witness of the epistles, which speaks of the Fatherâ€™s choice of a certain people to be redeemed in no uncertain terms (e.g. Romans 8:29-30; Ephesians 1:3-6; 1 Peter 1:1-2). We may learn further from the revelation of scripture that this people is chosen out of every kindred, tribe, tongue, and nation (e.g. Revelation 5:9), and that it will be called out only when the gospel is proclaimed in all the world (e.g. Matthew 24:14).
So how does this truth affect the task of the Christian missionary? First, it gives him a clear directive in the pursuit of the task: as the Church continues to spread across the world, believers may know that in their missionary endeavors they ought to target the kindreds, tribes, tongues, and nations which are yet unreached, because they know that the conversion of representatives from these peoples is the Fatherâ€™s will. Their task remains undone as long as there is any people group that has not heard the gospel, or that has not yet seen fruit from the proclamation of the gospel. Second, this understanding gives hope to missionaries laboring in the most difficult places. When Paul was experiencing opposition in Corinth, he was comforted by the realization that the Father had many people in that city, chosen for a redemption which had not yet been applied (see Acts 18:9-11). In the same way, the missionary who understands the biblical representation of the Fatherâ€™s role in redemption has a strong hope that his labor will not be in vain, and has cause to cry out to God in faith for the success which has been promised. Because God has chosen a people, our ultimate success is guaranteed. This foundational awareness of the Fatherâ€™s revealed role in the work of redemption drives a faithfulness which would otherwise wilt under the discouragement of unfavorable circumstances.
Consider as well the Sonâ€™s role in the work of redemption: he has determined to redeem the people God has chosen through his sacrificial blood, shed in their behalf; and in consequence of this redemption, he has won the right to return and judge the world, saving those who believe in him and condemning those who do not believe. Understanding this role clarifies the missionaryâ€™s task of proclaiming the gospel: for the account of this work is precisely the gospel he must proclaim. To the extent that one has not understood the role of the Son in redemption, he cannot proclaim the good news of that redemption. When Paul labored to bring the gospel to people, he emphasized Christâ€™s role as the returning judge and his resurrection from the dead, which had given him the authority to be Lord of the living and the dead (e.g. Acts 17:31; Romans 14:9). He also emphasized his shed blood, which serves as a fully acceptable propitiation for the sins of all who believe in Christ, and on that basis exhorted people to be reconciled to God (e.g. Acts 13:38-39; Romans 3:23-28; 1 Corinthians 1:23-24; 2 Corinthians 5:20-21). Now, to forget the part of Christâ€™s redemptive work which promises him the authority to come and judge the world, casting his enemies into eternal punishment, strips the gospel of its necessary context. Just asking a person, â€œDo you want to be saved?â€ is meaningless unless it is made clear what he must be saved from. But saying, â€œGod has raised his Son from the dead, vindicating his authority to return to the earth and judge all who are opposed to him; would you be saved from the wrath that he will soon bring upon the earth in great fury?â€ â€“ that provides the necessary background to display the surpassing goodness of the good news. But not only must Christâ€™s judging role be emphasized; so also must his atoning, propitiatory role be emphasized, or else the news is not good at all. Saying, â€œJesus has risen from the dead, and is Lord over allâ€ is only bad news for anyone still in his sins. To the extent that the missionary does not understand the role of the Son in the work of redemption, therefore, he is left without a message to take to the nations of the world, the message by which all the Fatherâ€™s chosen people will be called out.
Similarly, without an understanding of the Spiritâ€™s role in redemption, the missionary is apt to be frustrated. It is only through the Spiritâ€™s empowerment that the missionary can proclaim the good news with boldness and clarity (see Acts 1:8); and likewise, it is only through the Spiritâ€™s work of convicting and regeneration that the elect of the Father can understand and come to Christ (e.g. John 3:5-8). Understanding the role of the Spirit directs the means of praying for and pursuing the evangelistic task; it also provides the ongoing confidence in the missionaryâ€™s own secure position in the favor of God. The Spirit is sent to seal and guarantee the final salvation of all who have once come to Christ (e.g. Romans 8:11-17; Ephesians 1:13-14); and without that constant witness and encouragement, the missionary is apt to despair at his own condition, especially when his circumstances grow difficult.
So then, an understanding of the inter-trinitarian roles in the work of redemption is a necessary foundation for the Christian missionary, shaping the message he has to take, clarifying to whom he has to take it, and providing inexhaustible hope and encouragement along the way. But there is also another way in which the doctrine of the trinity serves as the means of Christian evangelism; and that is, it is only as the trinitarian nature of God is displayed in the lives of Christians that unbelievers will come into a relationship with this triune God.
In his last discourse, Christ revealed to his disciples the means by which the world of unbelievers would recognize that they were truly followers of Christ: and that means was nothing other than the love they had for each other, which is reflective of the inter-trinitarian love of the persons of the Godhead (see John 13:34-35). When believers are brought into a covenantal relationship of love which is reflective of the eternal trinitarian covenant of love, people take notice. Mankind was created to display the image of God, and until he does so, he is living a life devoid of ultimate purpose. Mankind was created to know and enjoy God; and when he gets a glimpse of Godâ€™s nature, in the lives of believers, he realizes that he wants something like that, but he does not yet have it. This is why, in John 17:21, Jesus prayed that the disciples would be one even as he and the Father were one â€“ so that the world would believe that the Father had sent him! When the world sees the blessed trinity reflected in the lives of the disciples, it is only then that they will believe in the actual trinity, the Father and the Son whom he sent.
So then, the shaping element of the doctrine of the trinity for the means of the Christian mission goes even beyond the fact that the knowledge of the redemptive work of the Godhead is a necessary foundation for taking the message to the world; in fact, the display of the inter-trinitarian relationships in the lives of the disciples constitutes a necessary means through which the gospel message may be understood and desired. -- from How the Doctrine of the Trinity Shapes the Christian Mission