HaRav Dov Lando
HaRav Dov Lando delivered a strong chizuk address in which he said:
What more can I say, seeing present here roshei yeshiva who instruct their students? But I will say something relevant to us all, to all yeshiva students: a ben yeshiva must bear this title not only within the yeshiva itself but also outside, and he must bear this constantly in mind.
The concept of chillul Hashem, creating a discredit to Hashem's Name, is something one must be very vigilant so as not to trespass. This is not measured only by one's actual conduct but also by what the public sees and expects of him. A Torah scholar/student represents the Torah itself so that any aberration that falls within chillul Hashem is indeed a most serious infraction.
The Chazon Ish offered a new insight in this concept which he derived from the Tractate Sanhedrin 107, where Dovid Hamelech considered worshiping idols to avoid chilul Hashem, showing that chilul Hashem supersedes even the three cardinal sins.
The Beis HaLevi explains this gemora by saying that Dovid Hamelech bowed to Hashem in a place where it seemed to the public that he was worshiping idols. The sin here does not fall within idolatry but rather is just chillul Hashem, since everything is judged according to what the onlooker sees and thinks.
The Chazon Ish derives the plain conclusion that desecrating Hashem's Name is more stringent even than worshiping idols, and he stated this many times. Chillul Hashem is so severe and so terrible that it is preferable to worship idols rather than to desecrate Hashem's Name.
I have also seen this in the response of the Rid (siman 53) regarding the rule of `let one be killed rather than transgress' in connection with chillul Hashem. One is forbidden to swear falsely before gentiles who realize that he is lying, since this constitutes chillul Hashem and does not supersede even preservation of life.
It is also stated in Sefer Yereim (siman 340) regarding the severe level of infraction of chillul Hashem that it is forbidden to accept charity funds from gentiles since this falls under that selfsame category.
Chillul Hashem is subjective to each person according to his spiritual level. Society expects him to conduct himself respectfully according to his station and if he falls short, he is causing a blow to Hashem's honor in this world in their eyes.
This is not an absolute thing but dependent on how others view him. If people consider him a talmid chochom, even if he is not one, he must act as if he were, that is, respectfully, especially in the eyes of the public. This principle applies especially when chareidim come in contact with secular Jews where one is regarded as representing the circle of Torah scholars. If he falls short, knowing that he is not one, and does not conduct himself as such, he is causing a desecration of Hashem's Name.
This transgression is especially severe since he is representing the very Torah! While we have no interest in contact with the street, nevertheless, one must comport himself in a seemly fashion as if he were, indeed, a talmid chochom, and not act strangely in ways that don't conform with the norm, for 'the Name of Hashem is upon him'.
Rather, outsiders should say, `How nice and refined are the ways of one who studies Torah. Fortunate is he and his teachers.' One must bear this in mind not only when he is conscious of the impression he makes upon others but also when he is not aware that he is the focus of other people's attention.