“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.” (Romans 12:1)
Which of us can say we know the mind of God so well that we can state definitely why He does what He does? Which of us can say why He even chose us? Although God has revealed much to us in His word, enough so that we can know His will for our lives, no man knows these things. God has shown us mercy. Each of us must then choose to respond to that mercy. And that is by becoming a living sacrifice.
We often think we can satisfy God in a piecemeal way, a little here, a little there and God will be satisfied. Then we can use the bulk of our time, energy and resources in pampering ourselves, indulging our fleshly appetites or pursuing the American dream. In reality we are trying to satisfy ourselves by giving Jesus a portion of what we have or some of our time. But Jesus does not want some of the things or money or time we have. He wants it all, everything, without reservation. This doesn’t necessarily mean that He wants us to spend more time in church or to go to some far-off mission field or pass out tracts on the subway. It doesn’t even involve following a whole bunch of rules and commandments that other people or even we may make up. Giving ourselves to Jesus means living the Christian life, avoiding sin, overcoming temptation, and loving and helping undeserving sinners. In order to do these things we must each become a living sacrifice.
The Lord wants us to willingly remain on His altar without flinching, or crawling off. He is not calling us to be physically slain. He calls us to be a living sacrifice, one that is continuous. God wants to consume us on that altar with His fire, to purify us and so He can use us as He sees fit. That we should want to do so willingly is an act of worship because in it we acknowledge we trust Him. We trust God because we have seen that He is loving and compassionate and faithful. He has shown us great mercy despite what we have done, despite what sins we still commit. We trust that God will do what is best for us, just as Abraham did when he went to sacrifice Isaac his son.