Therefore I urge you, brothers, in view of God's mercy, to offer your bodies as living sacrifices, holy and pleasing to God - which is your spiritual worship. (Romans 12:1)
The teaching method of the Apostle Paul was to make a presentation of doctrine followed by a practical application to our daily lives. In the first eleven chapters of his epistle to the Romans, he expounded upon the great doctrine of God's mercy. He now moves on to show its ethical implications for our lives.
Paul begins, not with an idea or a suggestion or a request, but with a heartfelt plea to the Jewish and Gentile believers: "Therefore, I urge you..." The word "therefore" brings us back to what has preceded - Paul's extensive treatment of God's great mercy to sinners who deserved nothing but condemnation, but have, by God's mercy, become his adopted sons and daughters. And he urges the recipients of divine mercy to "offer your bodies as living sacrifices..." This is not the first time Paul has spoken on this subject. Having shown that God's merciful treatment of sinners is not a licence to continue sinning but that, on the contrary, conversion to Christ makes sinning ethically unacceptable, he says, "Do not offer the parts of your body to sin, as instruments of wickedness, but rather offer yourselves to God, as those who have been brought from death to life; and offer the parts of your body to him as instruments of righteousness." (Romans 6:13)
Paul uses liturgical language when he says we are to offer sacrifices that are (1) living, (2) holy and (3) pleasing to God. Throughout the Old Testament, the priests offered dead animal sacrifices to God, whereas we offer living, holy sacrifices with our bodies: our hands, our ears, our feet, our tongue, etc. For example, the Christian mother who cares for her children - bathing them, washing their clothes, tidying up after them, playing with them, reading to them - is doing holy work; she is offering sacrifices that are holy unto God. And God is pleased. Even our moments of relaxation can be times of worship. To restrict worship to an activity that only happens on a Sunday is to miss the point Paul is making in Romans 12:1. Peter reminds the saints of (1) who they are and (2) what is expected of them. "You also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ." (1 Peter 2:5) Every Christian is a priest whose body is the temple of God. (1 Corinthians 6:19) Wherever there is a Christian, there is a priest who can offer spiritual sacrifices in the temple of God.
Therefore, every day we need to be aware that through our body - hands, feet, eyes, etc. - we are offering to God living and holy sacrifices. And our motivation is the realisation that we are the recipients of God's great mercy.