I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect (Romans 12:1-2).

Paul is speaking not to those outside the Church, but to those within. Not only are we sinful, and therefore prone to believe what we want to believe, but we are influenced far more by the thinking and assumptions of the world in which we live than sometimes we know.

Examples are, of course, legion, but let me suggest one in the arena of life. The promotion of sexual license rests upon two pillars: abortion on demand and contraception. The Catholic and Anglican churches—and many Protestant denominations—generally reject abortion, and often quite decisively. Contraception is a bit different. Protestant churches have either embraced contraception or are largely silent on the matter, their silence in effect giving tacit approval. The Catholic Church has remained clear in its opposition, but polls show that a majority of Catholics either reject the Church’s teaching on contraception or are skeptical of it.

For those who don’t know the history, until 1930 Catholics and Protestants were united in opposition to contraception. In a statement at the 1920 Lambeth Conference, the Anglican bishops were clear: “We utter an emphatic warning against the use of unnatural means for the avoidance of conception, together with the grave dangers—physical, moral and religious—thereby incurred.”
Yet in 1930 the Conference changed course, and the Anglican Church became the first to declare contraception legitimate: “Where there is a clearly felt moral obligation to limit or avoid parenthood,” the bishops announced, “the method must be decided on Christian principles.” While they went on to insist that contraception could not be used for reasons of selfishness, luxury, or convenience, the bishops failed to articulate the Christian principles that were to govern such decision-making—nor did they give the reason for their change in position. It is noteworthy, however, that this took place during the time when people like Margaret Sanger (the founder of Planned Parenthood) were pushing birth control as a way to “free” women from the possibility—imposed upon them by their own biology—of unwanted pregnancy. By the 1970s, when the sexual revolution was in full force in the U.S., contraception had become mainstream. It was largely accepted by the churches, with no caveats about selfishness or convenience. And, curiously, without theological justification.

This is not the place to argue the point concerning contraception. What I do want to note is that the Protestant churches welcomed it along with the rest of the world. The vision our culture came to embrace—promoted by Margaret Sanger and supported by the sexual revolution—was one of sex without consequences. Engaging in intercourse is a choice everyone should be able to make without constraint (even the constraints of our own biology), and to the extent that we need to resort to contraception or abortion to avoid the possible consequence of pregnancy, so be it.
What does all this have to do with Romans 12? In the end, our ability to see through the pattern of the world, and to be transformed by the renewal of our minds, depends on a willingness to worship, to present our bodies as a living sacrifice, holy and acceptable to God. Presenting our bodies to him means we understand that we are not our own, that we submit our visions and desires to him, even when they run against the grain of what we might believe or desire, and even when doing so is scary. In other words, worship is rooted in trust—that God created us, knows us, loves us, and that his ways are good, even when they are costly, even when we wish they were different. Apart from worship so understood, our minds will not be renewed, we will not be transformed, and therefore we will not be able to discern the good and acceptable will of God.