¹I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. ²And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.

I beseech you therefore, brethren, by the mercies of God – Because of the mercy that God has shown us; the apostle Paul is begging fellow Christians to live as he says here.

that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. – We are to give all we are to him (a living sacrifice.) The body is where our humanness resides, so be disciplined to resist sin and control the desires of the flesh (present your body). Strive to be holy and behave to please God because this is a reasonable thing to do in light of the mercy and grace that we enjoy.

And be not conformed to this world: – Do not seek the temporal pleasures or profane objectives of the secular world, that is Satan’s domain. Choose righteousness and do not be conformed to the spirit of the world.

but be ye transformed by the renewing of your mind, – The mind is where we struggle with sin. Live in God’s word that refreshes, renews, and keeps us following his will.

that ye may prove what is that good, and acceptable, and perfect, will of God. – We are to submit to God’s will, not our own. This is the foundation of being a witness to others of God’s wisdom, goodness, and sovereign perfection.