Rabbi Shalom DovBer of Lubavitch, the Rebbe Rashab, said:

A person who wishes to climb a mountain requires three basic things:

1) a thorough knowledge of the trails and pathways leading to the top;

2) sufficient strength and endurance to make the climb; and

3) the appropriate clothes and equipment.

The same applies to the spiritual climber who wishes to “ascend the mountain of G‑d” and come close to the Divine. He must gain a thorough knowledge and comprehension of G‑d and the ways of G‑d. He must possess the strength and endurance to conquer his animal soul and surmount the obstacles of his material existence. Further, he must avail himself of the “garments” and “tools” — the thoughts, words and deeds of Torah, which protect the soul from all adverse elements and aid its upward climb.

Sichos Kodesh, Behaalos’cha, 5711