קדושים תהיו

People often frame material excess as a possible issue of lack of tzniyus or other "mussar-dike" infractions which might make people feel less bound and restricted. They can just say "I am not on that level" and feel that they remain perfectly Halachic Jews in good standing. 

In fact - there is a din di-oraisa of קדושים תהיו which obligates everybody on every level. That includes a prohibition on over-the-top Gashmiyus [עי' רמב"ן].   

Someone was telling me about a neighborhood which is a Yeshivish version of Beverly Hills. Who lives there? People who can afford it. Who wants to live there? A lot more people who hope to one day be able to afford it. קדושים תהיו is not part of the conversation.

And it should be. 

Disclaimer: I am not advocating asceticism. Farshaitzich... Be comfortable. But don't drown body and soul in the Gashmiyus. 

And for a higher level - 

"ענין הקדושה הוא שיהיה האדם נבדל ונעתק מן החומריות לגמרי ומתדבק תמיד בכל עת ובכל שעה באלוקיו" [מסילת ישרים פרק כ"ו כביאור מדת הקדושה].