Rom.12:1] 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.
We have all heard the saying: ‘it’s easier said than done,’ and as easy as it is to just ‘say something,’ it is harder to put it into practice. And the question is asked, ‘how do I become a living sacrifice?’ our Father has provided for us the renewing doctrine whereby we can successfully put what He has said to us into practice. Notice in verse 2, Paul says “and BE not,” it is a decision the saint can make on his own by the doctrine which is according to godliness, and “by the mercies of God.” We are told to “put off,” “cast off,” “let not,” and many other exhortations given to us by our Father to teach the saint ‘how’ to ‘live’ unto Him in godliness. And as previously stated, saying something is a lot easier than doing it, but the only way we can be a living sacrifice is by ‘reckoning’ ourselves to “be dead indeed” not only to sin, but also to this ungodly world, and “alive unto God,” and thereby we can be “transformed by the renewing” of our minds.
Rom.6:11] Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord.
 Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.
 Neither yield ye your members as instruments of unrighteousness unto sin: but yield yourselves unto God, as those that are alive from the dead, and your members as instruments of righteousness unto God.
 For sin shall not have dominion over you: for ye are not under the law, but under grace.
Moreover, just as Paul says, “reckon yourselves to be,” he also says that the saint could “obey” sin “in the lusts thereof.” And in those verses, Paul refers to OUR lusts in verses 11 through 14, because he knows that we do not find it hard to ‘do’ the things that our hearts desire. But this is because we have been “conformed to this world,” and we have “served” this world, and the lusts of our flesh all our lives, we know how to do that, we just don’t know how to NOT do those things that “reigned” over us, and actually had “dominion” over our lives. We were ‘born into Adam,’ and by that; born into the ‘body of sin,’ we remained “under” its rulership and did “service” unto its ‘power.’ Our hearts and minds became “subject” unto this power, and dominion, we belonged to another’s “kingdom,” this is why Paul says in Colossians chapter 1:13, that He has “delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son.”
Rom.6:17] But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you.
 Being then made free from sin, ye became the servants of righteousness.
 I speak after the manner of men because of the infirmity of your flesh: for as ye have yielded your members servants to uncleanness and to iniquity unto iniquity; even so now yield your members servants to righteousness unto holiness.
Therefore, Paul presents unto the justified in Christ the ‘sanctifying gospel,’ we are taught in Romans chapter 6 what the death, burial, and resurrection of Jesus Christ accomplished for our sanctified lives, NOT JUST FOR OUR JUSTIFIED POSITION in Christ, but ‘how’ we are going to ‘now’ “continue” to live unto our ‘new Lord.’ We are taught that sin in our bodies, and our bodies under sin’s dominion had rulership, or ‘lordship’ over us, and we were its “servants,” and the reason why is given in Romans chapter 6, it was because of the “infirmity of” our flesh, but it begins with the hearts of the believer. It begins with what verse 17 sets forth; ‘obeying from the heart that form of doctrine which was delivered unto us.’ Because just as verse 12 points out to us; we allowed sin to “reign in your mortal body, that ye should obey it in the lusts thereof.” In other words, Paul teaches us that, we know ‘how’ to “yield,” “serve,” “obey,” and “live” unto another, and we are given the sanctifying doctrines of how this is done beginning in Romans chapter 6.
Rom.812] Therefore, brethren, we are debtors, not to the flesh, to live after the flesh.
 For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.
 For as many as are led by the Spirit of God, they are the sons of God.
Moreover, the issue with the justified in Christ becomes, how they are going to now “live” AFTER they have placed their faith in Christ alone. And as we further see in Romans chapter 8, being a “debtor” to our Father and His Living Word is how we are exhorted to walk as the “sons of God.” But notice the contrary way the saint could walk? And if we are not fully understanding and appreciating what it means to be a “debtor” unto our Father, and what it means to be the “sons of God” in verse 14, we WILL BE a “debtor” to “the flesh, to live after the flesh.” And the justified in Christ COULD “live after the flesh” as per verse 13, this is conditional, just as verse 14 says, “For as many as are led by the Spirit of God, they are the sons of God.” And those who have desired to be a living sacrifice, they too have come to understand to be a “debtor” to the “Father of Mercies.” And it is by those “mercies” that we are beseeched as “sons” to live by the provision that our Father has made for us, instead of making “provision for the flesh to fulfil the lusts therof.”
Rom.13:12] The night is far spent, the day is at hand: let us therefore cast off the works of darkness, and let us put on the armour of light.
 Let us walk honestly, as in the day; not in rioting and drunkenness, not in chambering and wantonness, not in strife and envying.
 But put ye on the Lord Jesus Christ, and make not provision for the flesh, to fulfil the lusts thereof.
Finally, notice how Paul says to just “cast off,” and “let us put on,” again, that may seem as it is easier said than done, but making provision for our flesh to fulfil the lusts thereof is how we live our lives, this walk is not hard for the saint, but as Galatians chapter 5 says, “walk in the Spirit, and ye shall not fulfill the lust of the flesh.” This “walk” is consistent with a renewed mind, but only a Spiritual mind of a son would see that he is a debtor not to his flesh, and that he should not obey his flesh, and not fulfil the lusts of his flesh, but understand and appreciate who he has been made in Christ as a son.
Gal.5:16] This I say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh.
 For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.