Rav Wolbe Warns Stringencies Can Lead to Arrogance and Sin

Rav Shlomo Wolbe was raised in an secular Jewish home and received his education at the University of Berlin (1930–1933). During his university studies he became a baal teshuva through the efforts of the Orthodox Students Union V.A.D. (Vereinigung jüdischer Akademiker in Deutschland). After university he attended the Hildesheimer Rabbinical Seminary. He continued to study at Rabbi Boczko’s yeshiva in Montreux, Switzerland. He then attended the Mir yeshiva in Poland, where he became a student of the mashgiach ruchani, Rabbi Yeruchom Levovitz, and, to a lesser extent of Rabbi Yechezkel Levenstein.

He published his first volume of Alei Shur in 1966, which contains his mussar (“ethics”) analysis on a proper regimented life of a yeshiva student. The second volume published 20 years after the first was an intense glimpse into his actual mussar workshops for developing elevated character traits. The book contains step by step instructions and specific exercises.

Rav Wolbe believed that the student should not rely on habit or emotions, rather they should structure their lives. “The greater the person is, the more organized is his life.” (Alei Shur, Pg. 68)

Rav Wolbe felt that there are four basic areas aside from the regular Gemara curriculum of the yeshiva that the yeshiva student should master:
He must know the Halakha (Jewish law) that affects him through the Mishnah Berurah.
He should know Chumash with the commentaries of Rashi and Ramban as a basis for one’s hashkafah.
He should know Pirkei Avos with the commentary of Rabbeinu Yonah (a cousin of Nachmanides) as a basic primer in acceptable character traits (midos).
He should know Mesillat Yesharim (by Rabbi Moshe Chaim Luzzatto) which he calls “the ultimate compendium dictionary for midos.” It must constantly be delved into.

(above from Wikipedia)

In the Sefer Rav Wolbe on Chumash, Parshas Chukas, published in 2014, he says:

“Although one must adhere to every halachah, a person should be wary of stringencies. If abiding by a stringency will cause him to become conceited about his high level of spirituality, then he is better of without it. It was because Bnei Yisrael were on such a high spiritual level – they merited having Hashem’s Shechinah reside in their midst – that they became haughty and subsequently sinned.”