"My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous." 1 John 2:1
There is a very helpful trend in certain evangelical circles in emphasizing God's unmerited grace to us which cannot earn. Along with this trend has come a certain wariness of any saying "ought" or "should," so that it has become hard for me to see what these people do with the many passages which command Christians to do things. There are oughts and shoulds in even the New Testament, and even in the epistles--it is not just in the sermon on the mount, where one might argue that it was Christ reinforcing the impossibility of following the law. We are commanded to love one another, to forgive one another, to be humble. That we will fail is given as well, yet the goal remains "that you may not sin."
It is right to emphasize that we have unmerited grace, and that it is only by God's grace that we live--in Christ! What we must be wary of, however, is that this grace does not become diluted so that there is nothing which our lives affirm us as being saved, or needing to be saved, from. If this grace saves from sin, then our lives ought to reflect that savedness--I say this ought as a logical, not a moral, ought. If this grace is a union with Christ, then this (too?) should appear in our lives.
Look: what we lack is righteousness, and what we receive by grace unmeasured, vast and free is Christ's righteousness--Christ's own life--and this is also what--better: who--we seek. In all of life, we seek Christ, for he is our life. For a Christian, if he truly sees his life as hid with Christ, then, logically, he ought to treat Christ as savior and Lord--as the one who has dominion over his life. If suicide is wrong generally, then how much more denial of Christ! If, then, we receive this life, then we will live in a way that reflects having received the life of Christ. We will live like he lived, for it is he who lives in us.
The danger is in making it all and only grace to us, or all and only the actions we are to do. Rather, it must be Christ alone, much more than grace alone (for grace alone only makes sense as shorthand for Christ alone). It is Christ's life given to us, and Christ's righteousness which we as Christ's body live out. It is because we have a righteousness which is not our own that we also have a life which is not our own, and because it is not our own, but Christ's, it is a life which must be submitted to him. We live, then, as Christ lived, not by our own effort, but because we, by faith, really have Christ's living in us, bleeding out. Nothing I do is righteousness, but only what Christ does in me.
Grace becomes antinomianism when Christ's life is set apart from grace. Christ's life for us is grace to us. Grace may not be left as a mere concept, but must be embodied, lived out in the community of faith, as the life of Christ. Grace therefore requires us to follow hard after Christ. Grace is not grace if it does not bind us to Christ--"let thy grace, Lord, like a fetter, bind my wandering heart to thee." Indeed, grace is grace in that it binds Christ's righteousness and thus Christ's life to our own so that Christ died for our transgressions and was punished for our iniquities, and so that Christ's life of perfect obedience to God is our own. This is grace: not that sin does not matter, but that sin matters so much that God sent his Son to free his people from sin. So, now, since we are free from sin, by God's grace--by following Christ, by being disciples of Christ, by holding fast to the life of Christ (which is to say, by holding fast to the righteousness which we have been given in Christ)--let us live in this freedom, not freedom that allows us to sin, but freedom from sin. To sin is to reject the freedom, and the life which we have by union with Christ.
I write this against any antinomian tendencies which might be about to develop, but I must also provide the caution on the other side. If we ever forget that our actions are by Christ, that our righteousness is only in Christ, and that we are saved by Christ alone. If we ever begin to think that we somehow earned union with Christ, then we will have returned to legalism. The key is this: Jesus Christ. He is our life, and thus our righteousness, our strength, our hope, and our peace. It is in him that we are in love. It is through him that we do what is right, and know what is good. To speak the truth in love it is necessary to know Christ who is truth and to be hid with Christ so that we are in God who is love. Apart from Christ I can do nothing! Yet in him I am used to accomplish things I do not even know. And all the glory must go to God, for it is God in the person of Christ who, by the power of the Holy Spirit, accomplishes all these things in me.