In Romans 12:1 the Apostle Paul writes: “Therefore I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship.”  Realizing the audience the author is addressing here gives us a key insight:

He writes: “I urge you therefore BRETHREN.” He is addressing “brethren” — fellow Christians.  This message of holiness is not for a person who does not know Jesus as their Savior.  The exhortation to holiness is wholly based on “the mercies of God” which He has already shown you (see yesterday’s devotion here). If you have not been shown this mercy, then there is absolutely no motivation for you to be holy.

This is a vital point.  Holiness makes no sense to a lost person. Why should they make the effort to deny their natural desires, and sacrifice what seems good to them?  That has no appeal to them whatsoever.  Which explains the conduct of a lot of people, even many who attend church. If there is no motivation to holiness, you can be sure there is no existence of salvation!  Holiness only makes sense to “brethren”, who are motivated by “the mercies of God” which they have been freely given.