Merely Hearing Lectures or Studying Books is Useless

You should put all... instructions into practice; not merely listening to lectures. Lecturing is only a little bit of intellectual play, a little intellectual gymnastics or amusement. Whatever you hear, you will have to put it practice.

You have heard many lectures. You will have to put what you have learnt into practice. Then only will you grow. Merely hearing lectures or studying books will not help you in making you into a superman. You will have to practise. Control the mind and control the senses. This is the time for you to spend a few hours or a few minutes in prayer. Be regular in your prayers. Make it a habit of getting up at 4 am. This is brahma-muhurta --- very efficacious for japa, prayer and meditation. You can also study in Brahma-muhurta. What you can study in six hours later on, you can stay in one hour during the brahma-muhurta. 

Source: pgs. 32, 19, Sivananda's Lectures (abridged version) During All India and Ceylon Tour --- 1950.