I respect what she did. It seems rare that people today will give up money or fame because of their beliefs.
But that does not comment on your question or statement so I will give you my thoughts:
Yes, it is by grace we are saved through faith, just as Paul wrote to the Ephesians but remember what Paul wrote to the Corinthians about the strong and weak members of the Church - some were comfortable eating meat that had been sacrificed to an idol whereas others felt it was a sin to eat the same meat. So what did Paul say? Although Paul said it was not wrong to eat the meat, he also said that a person needs to act in accordance with the dictates of their conscience - if they thought it was a sin to eat, then THEY should refrain from eating.
I think this is the same way you need to see this situation with the model. Regardless of what you or I may think, her conscience was bothered by what she was doing and, therefore, she choose the correct path for her and did what she felt was correct to do to not hurt her relationship with the Lord.
So, yes, it is by grace but grace is not a license for sin (which you already know, I am certain) and it also gives us the liberty to do some things and also the liberty to choose NOT to do some things if it goes against our conscience - so she acted within the sphere of grace and choose NOT to do something.
But what is it exactly about modelling that she thought was a sin? It doesn't hurt anyone. I suppose modelling makes a person into an object to look at, for money. And that sort of obscures and cheapens their humanity.
I heard once that all religions seek to have a monopoly on pleasure, because then people don't get distracted from religion by the everyday world. So religions say that all pleasure must come from the religion itself, or at least be licensed and controlled by it in some way. Any pleasure outside of the control of religion is considered a sin just because it is a threat to the religion.
The woman was arrayed in purple and scarlet, and adorned with gold and precious stones and pearls, having in her hand a golden cup full of abominations and the filthiness of her fornication.
MYSTERY, BABYLON THE GREAT,
THE MOTHER OF ALL HOOTERS AND LAUGHS
AND OF THE RELIGIOUS ABOMINATIONS
OF THE EARTH.
I saw the woman, wet with the blood of the saints and oozing with the blood of the martyrs of Jesus. And when I saw her, I marveled with great amazement. This smells funny, so I wondered. We need to put this on televison and make some dough.
Patrick: I don't know exactly what all the factors were that led her to her decision but she did say in an interview that her husband did not like her modeling (so, maybe that was a source of conflict in their marriage?) and she also said that her 9 or 10 year old niece said she needed to lose weight so she could look like her. She said that made her realize how much of a role model she was being for the younger girls. So, like allot of things in life, there seems to be a multitude of factors that probably came together at once and she just decided that modeling for Victoria Secrets was not the right path for her (although she still models, I think but just not lingerie). Does anyone know anything more than this? This is what I heard her say in an interview.
"But what is it exactly about modelling that she thought was a sin? "
I probably should not have used that expression because, in the interview I heard, she never used the word "sin". She just gave the reasons I wrote above and also said she made her decision based on her faith and because she was a Christian - so she never used that expression and I need to clarify that. I think, and this is only my thoughts, that she felt like she was setting a bad example for other women (especially younger girls) that women were just an object for men to ogle over and lust at - but she never stated that in those clear terms so that is just my interpretation and could be wrong.