Legalism is a basic outgrowth of human nature. Most people - at least those who have not grown beyond their own spiritual adolescence - want rules and boundaries and concrete structure. Surely, their instincts tell them, one could not hope to please God without doing one's best to follow the rules and to make others do the same. Why else would God have spoken to us through the Bible if not to tell us how to conform by laying down the letter of the law?
That the Bible itself continually gets in the way of such expectations is of little consequence. Since a consensus has been reached in advance that the Bible must be a book of rules and regulations, there can be no question that those passages that talk about grace and freedom don't really mean everything that they seem to say.
Thus, it is without any sense of irony that many Christians will put on their "It's a relationship, not a religion" T-shirts even as they proclaim a Christianity that sacrifices true relationship in favor of a code of regulations as strict as any found in any other man-made religion. The more thoughtful will nuance their arguments and acknowledge that there are, in fact, gray areas that no interpretation of the Bible can fully resolve, but in the end they're still left playing a game of "yes, but."
-Yes, we are saved by grace and not by our works, but if you willfully break the rules too many times then God's grace isn't sufficient to save you.
-Yes, God's love is unconditional, but you still have to meet our standards before he'll fully accept you.
-Yes, nothing in all of creation can separate us from God's love, but certain 'important' sins can.
-Yes, Jesus freely associated with the lowest of the low, but he did so to change them.
That last statement is worthy of closer examination, as it is the one that non-legalists would agree contains an element of truth. The prostitutes, tax collectors and other sinners that Jesus reached out to went away transformed, and changed their lifestyles accordingly. What the legalists miss, however, is that Jesus transformed them purely through the power of his love. He did not scold them or lecture them or talk down to them, nor did he demand that they change as a condition of his acceptance. Indeed, he saved his harsh words for those who proclaimed themselves godly based on their outward behavior, and who shunned anyone who didn't live up to their high standards.
The one time Jesus did exhort a sinner (John 8:11), it's worth noting that he did so after he had saved her from being executed, and after all of her accusers had left; as far as any of them knew, Jesus might have sent her on her way without another word. He did not make her repent before he rescued her, nor did he threaten her with future punishment should she sin again. He simply showed her mercy and encouraged her to avoid repeating her mistake.
The New Testament contains numerous exhortations to abandon our sinful nature, and many theological treatises have been written about how we can overcome "the flesh." But what if "the flesh" refers not just to our propensity to sin, but to the entire way that we try to relate to God? What if our demand for explicit instructions on how we should order every detail of our lives is, in fact, a way for us to avoid surrendering control to God?
What if dying to ourselves has less to do with avoiding sin than it does with abandoning our rules-based approach to life? By focusing our energies on all the dos and don'ts that we can piece together, are we really pursuing holiness or are we making the very sins that we seek to avoid the centerpieces of our lives?
Abandoning our old system of black-and-white rules might seem like an invitation to chaos, if not death itself - and yet dying to ourselves is precisely what we are called to do as Christians. It might seem as though we are abandoning morality - yet it's precisely because morality is important that the old system of clear-cut, one-size-fits-all rules must be abandoned.
Surrendering our lives to God means giving up everything, including our right to have everything neatly spelled out for us. Living under a law-based system enables us to remain in control of our lives, and to extend that control over the lives of others. Living under grace requires us to permanently give up that control and to become fully dependent on God's Spirit for every step that we take through life.
Few things could be more frightening, but in the end, nothing could be more empowering.