Rav Kook was not a chossid in the classical sense. He was a "Volzhiner talmid" and very close to the Netziv. His home was not a chasidic one [although he was under the influence of a mashpia from chabad at a young age]. He followed the Vilna Gaon in his daily halachic practice.
All of this spells "Not Chasidic".
However....
From his youth he would learn sifrei chasidus and particularly Chabad chasidus. Many of his teachings are rooted in chasidic sources.
One time on Erev Shavuos his secretary [R' Glitzenstein] found him pacing with ecstacy while holding a Likutei Torah [written by the Alter Rebbe of Chabad] open to the peirush on Shir Hashirim. He exclaimed a number of times "From this maamar you see open ruach hakodesh!!"
He also learned a great deal of Toras Rebbe Nachman of Breslov [before it was so "in" - so, incidentally did Rav Dessler] and revealed that "אני נשמת רבי נחמן". He had a Likkutei Tefillos [by Rav Nosson, Rebbe Nachman's talmid] next to his makom hatfilla and he would look into the sefer from time to time.
When he met the Imrei Emes [son of the Sfas Emes] he quoted passages of the Sfas Emes by heart. When he went on a fund raising trip abroad one of the only sfarim he took with him was a Sfas Emes. He said that you have to learn the Sfas Emes like a rishon.
Rav Hadari wrote an article in הראי"ה [page 154-167] on the connection between the Rav and Rebbe Tzadok Hakohen of Lublin.
[For many sources see R' Tzuriel's Otzros Hara'ayah Vol. 1 214-217]
Yet - he had strong criticisms of chasidus....
I would like to share some of those criticisms and what we can learn from the sugya of "Rav Kook and Chasidus" in a future post.
