"Salvation by faith alone" ("saved" being un-Biblicallly defined as "definitely going to heaven") is often argued, based Romans 3:19 - Romans 5:1; what about Romans 14:23 which teaches that sin has the power to compromise justification (even if temporarily)?
Romans 14
23But the one who doubts is condemned if he eats, because his eating is not from faith; and whatever is not from faith is sin.
Condemnation is the opposite of justification.
If this loss of justification had no bearing on salvation (justification precedes salvation in Romans 10), then it would be inconsequential, but 1) sin is never inconsequential, and 2) why even mention it? Doesn't this loss of justification correspond, instead, to Romans 8:12-13 which teach that only those who "by the Spirit mortify the deeds of the flesh" will live and not die (as Adam died for sinning)?
What's interesting is that, here, we see the idea of "justification by faith" seemingly extended into "actions which proceed from faith" ("works of Law" proceed from sinful flesh Romans 8:3, but what we are discussing here are "works that proceed from God--which God works in us")--and, just as in James 2, justification and salvation hinge upon working according to faith.
the same man that said justified by faith said whatever is not from faith is sin so both are true therefore just what is whatever is not from faith is sin.
to look at what you deliberatly taken out fof context in its context:
Rom 14:14 I know, and am persuaded by the Lord Jesus, that there is nothing unclean of itself: but to him that esteemeth any thing to be unclean, to him it is unclean.
Rom 14:15 But if thy brother be grieved with thy meat, now walkest thou not charitably. Destroy not him with thy meat, for whom Christ died.
Rom 14:16 Let not then your good be evil spoken of:
Rom 14:17 For the kingdom of God is not meat and drink; but righteousness, and peace, and joy in the Holy Ghost.
Rom 14:18 For he that in these things serveth Christ is acceptable to God, and approved of men.
Rom 14:19 Let us therefore follow after the things which make for peace, and things wherewith one may edify another.
Rom 14:20 For meat destroy not the work of God. All things indeed are pure; but it is evil for that man who eateth with offence.
Rom 14:21 It is good neither to eat flesh, nor to drink wine, nor any thing whereby thy brother stumbleth, or is offended, or is made weak.
Rom 14:22 Hast thou faith? have it to thyself before God. Happy is he that condemneth not himself in that thing which he alloweth.
Rom 14:23 And he that doubteth is damned if he eat, because he eateth not of faith: for whatsoever is not of faith is sin.
hence pork unclean for consumption amongst many especially Jews. this has nothing to do with one's salvation does it?
justified by faith applies to salvation, not what may or may not be right for some one to eat.