The doctrine of the active obedience of Christ has come under attack in various quarters in the contemporary church. In Presbyterian churches, it has been questioned by some in the Federal Vision movement; in New Testament scholarship, the New Perspective on Paul has argued that this doctrine has no foundation in the Pauline text; in Baptist theology, it is denied by the "New Covenant Theology" movement as well as certain forms of dispensationalism; in Lutheran churches, it has been rejected by Gerhard Forde, who proposes that any contention of the imputation of Christ's active obedience is based on a merit scheme foreign to the theology of Luther. Because of these challenges, it's a necessary question for the modern theologian to ask: is there validity to the teaching of Christ's active obedience?
Hoenecke describes the traditional Lutheran approach to active obedience writing, "So then, according to Scripture, that through which Jesus furnished satisfaction is his entire obedience (obedientia vicaria universalis), which is partly a doing (obedientia activa), namely, fulfilling the law, partly a suffering (obedientia passiva), namely, enduring the wrath deserved by us." (ELD III, 185) The believer is justified through faith by the imputation of Christ's obedience. This includes his active fulfillment of the Law which is counted to us, along with his death by which the Law's penalty has been paid. Certain evangelicals, like Robert Gundry, have argued that the second part of this is correct, but there is no Biblical basis for the imputation of Christ's active obedience.
I think what is needed is a balanced approach to this issue, with a frank admission that the active obedience of Christ is not as Biblically apparent as we have proposed that it is. In Reformed circles, I often heard the active obedience of Christ equated with the gospel itself. Look for example at this explanation of the gospel from D. James Kennedy where he equates the gospel with the imputation of Christ's perfect life. You have broken the Law. Christ obeyed the Law perfectly. Through faith, his obedience becomes yours. While I don't reject such a statement, as I think it can be demonstrated to be in line with Biblical revelation, this is not the way that the Apostle's spoke of the gospel. Rather than the active obedience of Christ under the Law, the central message for Paul, Peter, and John was the death of Christ, and his resurrection. Look for example at Romans 5,
"Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men. For as by the one man's disobedience the many were made sinners, so by the one man's obedience the many will be made righteous. Now the law came in to increase the trespass, but where sin increased, grace abounded all the more, so that, as sin reigned in death, grace also might reign through righteousness leading to eternal life through Jesus Christ our Lord." (Romans 5:18-21)
This has often been used as a text to defend the concept of Christ's active obedience, due to the contrast between the disobedience of Adam and the obedience of Christ. However, note that what is contrasted here is "one trespass," and "one act of righteousness." While some interpreters (John Piper and Robert Reymond for example) argue that "one act" can in fact refer to Christ's full life of obedience, the more obvious interpretation is that Paul is indeed speaking of one righteous act of Jesus. It is more likely that this "one act" spoken of by Paul is the cross, because earlier in that same chapter Paul writes that we are "justified by his blood."(Romans 5:9) Because Paul is following an extensive discussion of the cross with this "one act," they are likely the same event.
There really is no explicit statement in the epistle to the Romans that Christ's active obedience is in any sense imputed to the Christian for righteousness. This is odd, since Romans is Paul's most detailed discussion of the doctrine of justification. Pauline interpreters are right, due to this fact, to question the centrality of this idea in Paul's thought. It is unfortunate fact of history that the concept of active obedience has often eclipsed that which Paul does connect to justification more clearly: the resurrection. In Romans 4, in the midst of Paul's most detailed discussion of justification, he writes that Christ "was delivered for our trespasses and raised for our justification."(Romans 4:25) While I could give numerous examples of sermons I have heard which emphasize Christ's active obedience as essential to justification, I could probably count on one hand the number of times I have heard the resurrection connected with justification in any sense. This is where I think a lot of the contemporary challenges to the traditional approach to Christ's active obedience are insightful. N.T. Wright, some of the Federal Vision writers, and others have sought to place the resurrection back in a central position.
So my primary concern here is not with the doctrine of the imputation of Christ's active obedience itself, because I think its validity can be demonstrated, but with the centrality of this theme. In Paul's mind, Christ's righteousness most certainly is imputed through faith alone. One has faith, grasps Christ, and his righteousness becomes the believer's in justification. However, this righteousness, in Romans, is connected with Christ's death and resurrection. That isn't to say that Paul doesn't also have the active obedience of Christ under the Law in mind, but it isn't explicit.
Another major problem I have with equating the active obedience of Christ with the gospel (I have talked to some people who argue that a belief in the active obedience of Christ is necessary for one's salvation) is that this concept isn't present in the early church, or (at least not explicitly) in the writings of Luther. The fathers certainly thought that Christ's life was important. Jesus needed to live a sinless life, and needed to become an adult so that humanity could be recapitulated in his person, but there isn't any talk of the imputation of Christ's active obedience to the Law. To equate active obedience with the gospel is to say that the fathers didn't understand the gospel. I don't see how one can genuinely propose this. I also don't see the doctrine in Luther's own writings. For Luther, Christ's righteousness is primarily connected to his death and resurrection. There are certain hints at the imputation of Christ's Law-keeping, but it isn't explicit and certainly is not Luther's central concern.
The Formula of Concord does confess the concept of Christ's active obedience:
"Therefore, his obedience consists not only in his suffering and death but also in the fact that he freely put himself in our place under the law and fulfilled the law with this obedience and reckoned it to us as righteousness. As a result of his total obedience-which he performed on our behalf for God in his deeds and suffering, in life and death-God forgives our sin, considers us upright and righteous, and grants us eternal salvation." (FC SD III.15)
The Lutheran fathers rightly placed this idea in the lengthy discussion of justification in Article III, but they didn't make it the central aspect of Christ's righteousness. There is much more space devoted, in the Confessions, to the death and resurrection of Christ than to his active obedience. If I were asked what Biblical precedent there is for the idea that Christ fulfilled the Law on behalf of humanity, there are a couple of texts I would point to which hint at this idea. Galatians 4 speaks of Christ as one who was "born under the law, in order to redeem those who were under the law." (Galatians 4:4-5) Christ was born under the Law for the sake of those who were under the Law, in order that the Law might be fulfilled in himself, and its penalty might be paid. Regarding Jesus' baptism, Matthew writes,"But Jesus answered him, “Let it be so now, for thus it is fitting for us to fulfill all righteousness.” Then he consented." This points to the fact that Christ's righteousness consists not only in his death, but also certain aspects of his life. If we take these passages together, that Jesus life has something to do with his righteousness, and that it was necessary for Jesus to be born under the Law, and put these ideas together with the Biblical theme that the Law requires perfect obedience, it becomes apparent that Christ's righteousness consists partly in his obedience to the Law.
Since the Scriptural texts really aren't that strong on this theme, I think the best way to go about this idea is through the nature of Kingship. If you look at the Old Testament, and the way that Israel was treated under the covenant, it is apparent that the obedience/disobedience of any given king doesn't only affect the welfare of that individual king, but of the nation as a whole. The king is representative of the people. An obedient and righteous king causes God to bless Israel. An unrighteous king causes God to curse Israel. If Jesus is truly the fulfillment of the Davidic promise as the true son of David and eternal king of Israel, then it's a given that his righteousness plays a representative role. I think this is the context in which we can genuinely speak of the active obedience of Christ. I understand why we speak of the "merit of Christ" in this discussion, because of the medieval context in which these ideas were formulated, but maybe we would be better to speak of Christ's faithfulness, or his covenantal obedience, rather than the imputation of his active merit. That would point to the Old Testament roots of this concept, and might settle the fears of some that the idea of Christ's active obedience is grounded in Medieval scholasticism, rather than the Biblical narrative.