It is, therefore, when one knows how to reserve one's energies by repose, and when one knows how to concentrate and sharpen one's intellect, that this magnetism remains in a right condition. What generally happens is that it is the intelligent person on whom a great responsibility falls. Much more is asked of him than of others who lack intelligence. If he does not give a rest to his mind by knowing the manner of repose, and if he does not concentrate and by it sharpen his intellect, naturally, just like a knife which is always used, it will become blunted; naturally the continual use of intellect will make him short of funds.