Once, at a chassidic gathering, the 5th Lubavitcher Rebbe, Rabbi Sholom Dovber, said the following:
In Heaven, one may not enter the heavenly chambers unless one is deserving; if one isn’t they cannot enter. This is true even if the individual is of a special soul who is great in his understanding of Torah and his grasp of G-dliness.
Accepting the yoke of Heaven and the simplicity of fear of Heaven are the keys that open the lock to the doors of all heavenly chambers.
(Igros Kodesh, Previous Lubavitcher Rebbe, Vol. 6 Pg. 272)
