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 weaknesses? - 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? Strength, O man, strength, say the Upanishads, stand up and be strong.
If you can force your heart and nerve and sinew to serve your turn long after they are gone, and so hold on when there is nothing in you except the will which says to them: 'Hold on!'
As the gardener, by severe pruning, forces the sap of the tree into one or two vigorous limbs, so should you stop off your miscellaneous activity and concentrate your force on one or a few points.