Romans 12:1-2

What other response is there other than to offer the totality of our being in service to God as 'living sacrifices' in view of His mercy through Christ!! This is true worship to our God, holy and pleasing to Him. What other response can there be towards the One who had every right to crush us because of our sin, and yet chose to have such compassion upon his fallen world.
In offering ourselves in the totality of our beings to God, Witmer (1983, pp. 487-488) offers some helpful insights into this passage. He writes that Christians must not conform to the pattern of this 'present evil age' (Gal 1:4, cf. Eph 1:21), rather we must be transformed (keep on being transformed) through the renewing of our minds. Here the mind is seen as the control centre of one's attitudes, thoughts, feelings, and actions. As one's mind is made new by the spiritual input of God's word, prayer, and Christian fellowship, his or her lifestyle keeps on being transformed. All this can only be enabled by the power of the Holy Spirit as God works in us to will and to act according to His good purpose!
As believers are transformed through the renewing of their minds, they will then be enabled to ascertain what the will of God is as they travel through this life. And as experience tells us, His will is always good, pleasing, and perfect!

Rom 1:18-32

Indeed, humanity is without excuse for God has revealed Himself through His creation (Rom. 1:19-20). When we couple this with God sovereignly positioning the nations so that they would perhaps reach out and find Him (Acts 17:26-27), we observe humanity's resposibility before God. We must always be mindful however, that even though one may reach out to God even in an unsaved condition (as I did at age 27 through a difficult life situation), we simply cannot enter into a relationship with Him but by His gracious calling (John 6:44).
Back to humanity's resposibility, it has been good to have had impressed upon me, the fact that sin is not so much individual acts, but rather it is a failure to acknowledge God for who he is(Rom. 1:21, 25, 28). Thus the horror of being 'given up' (1:24, 26, 28) to all kinds of evil and the resultant effects, not the least of which is a depraved mind!
Praise be to God that he has restored us through Jesus to a relationship with Himself, such that we may live the life He intends for us by the Holy Spirit (Rom. 8:1-17), a life characterised by a mind of 'life and peace'

I guess I'm a bit of a devotional thinker at times. As I reflect upon Romans 12:1-3which is the start of his practical application (subsequent to his doctrinal one, per John Witmer), the theme of God's mercy and grace comes through here. Do we, (DO I) truly offer ourselves to God as living sacrifices in view of His mercy? The gift of faith is especially precious to me, as I recall a time back in 1989 when I was on Callala Beach, slumped over and thinking my life was over. God in his grace gave me a vision of letters that looked like gold, almost dripping gold which spelt FAITH and He spoke into my heart and said 'faith is a gift.' He subsequently empowered me to get up, take hold of my 7 year old daughter's hand and walk home. ..Who am I O GOD that you should consider me a fallen and weak creature, surely you are a merciful God, slow to anger, abounding in love and faithfulness, and full of compassion!!! Surely we cannot think of ourselves more highly than we ought to, for indeed it is by grace through the GIFT of faith that we belong to Him, to the praise of His glory!!