"I 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. And 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," Romans 12:1-2.
The word "therefore" leads us to the start of the practical section of the epistle, that of applying the truths Paul has set forth in chapters 1-11. How practical and useful the gospel is! It is that heavenly ointment whereby the wounds and bruises of sin are mollified. (Isaiah 1:6.)
Unlike the ointments compounded by men which are very limited in their applications, serving only to address one or maybe two ailments, the gospel ointment is universal. It treats all of man's ills and that most successfully. So said Isaiah the prophet and Peter the apostle. "But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed," Isaiah 53:5
"Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed," 1 Peter 2:24.
Healing from our sins comes through Christ the Ointment of Heaven. The first application of the truths that Paul has set down in the previous eleven chapters is found in the exhortation, "Present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service."