Strength, strength is what the Upanishads speak to me from every page. This is the one great thing to remember, it has been the one great lesson I have been taught in my life.
Strength, it says, strength, O man, be not weak. Are there no human weakness? – says man. There are say the Upanishads, but will more weakness heal them, would you try to wash dirt with dirt? Will sin cure sin, weakness cure weakness…. Ay, it is the only literature in the world where you find the word ‘abhih’ ‘fearless,’ used again and again; in no other scripture in the world is this adjective applied either to God or to man…. And the Upanishads are the great mine of strength.
Therein lies strength enough to invigorate the whole world. The whole world can be vivified, made strong, energized through them. They will call with trumpet voice upon the weak, the miserable, and the down-trodden of all races, all creeds, all sects, to stand on their feet and be free. Freedom – physical freedom and mental freedom, and spiritual freedom – are the watchwords of the Upanishads.
(Source: Ccomplete Works, Vol. III. Eighth Edition, pp. 237-38)