I’ve heard this before, in the context of how one lives their life. For example, “Oh, you don’t have to live such and such way…it’s not salvific!”
I agree it does not merit anything for salvation. However, salvation is a process. It starts with God’s sovereign act of changing the dead heart to a living one, a passive act on man’s part, and it continues throughout the life of the person, ending in glory. That time in the middle is the sanctification process, something the Holy Spirit does in the life of the individual by making them more holy, or Christ-like, which is by giving the person Christ’s graces, the fruit of the Spirit:
Gal 5:22-23 – “22 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, 23 Meekness, temperance: against such there is no law.“
Faith and love are the main drivers of the Christian, and with those comes obedience to God in His direction in the Bible, and the Bible would have Christians not love the world and not be conformed to it:
1 John 2:15 – “Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him.“
Rom 12:2 – “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.“
Using the example of how one dresses, the Bible would have Christians dress modestly. And in that modesty, given the world in its view on life and how to live it is one of a Christian’s main enemies (along with Satan and a person’s own carnal man), why would a Christian want to be as close to the way the world dresses, without supposedly stepping over the line, and not be as far away from the way the world does things, like Lot and his family escaping Sodom, not looking back desiring to be closer to it…like Lot’s wife?
So, Christianity requires OBEDIENCE to these commands, which (obedience) stems from love for Christ, which is a fruit of the Spirit, which brings sanctification, in the process of SALVATION!
Further, as I mentioned, a Christian’s enemy is his carnal man, which I believe is a person’s greatest enemy:
1 Pet 2:11 – “Dearly beloved, I beseech you as strangers and pilgrims, abstain from fleshly lusts [desires], which war against the soul;“
Our carnal man is at war with the soul. Part of our duty in our Christian walk is to war against our spiritual enemies.
As graces grow, the carnal man is brought lower and lower in the mortification (death-bringing) process of that carnal man. The means of denying the carnal man we have been talking about can help in that process. Again with dress, dressing modestly can help curb pride and vanity, things contrary to God, His nature and holiness. Mortification is a duty of ourselves, and as with graces, it is a work of the Spirit in the sanctification process, for which He uses means. And then, why wouldn’t a Christian want to dress in a way that brings the most mortification of pride and vanity, coming against sin in the strongest way possible?
Why would a Christian feed its enemy? A Christian should not, and ignoring this can be eternally dangerous:
Gal 6:8 – “For he that soweth to his flesh shall of the flesh reap corruption; but he that soweth to the Spirit shall of the Spirit reap life everlasting.“
And so, while nothing we do in our lives merits salvation, there are means of sanctification in the salvation process, and it is important for a professing Christian to consider how he/she live their life in light of the Bible’s directions and how Christ lived His.