The more you try to forget something, the more you remember
it. You cannot forget anything. Any conscious attempt to forget strengthens the
thought; you remember it all the more.
To forget any thought, do not think about it, think about
something else. That is, put your mind somewhere else, then the mind goes away
from the unwanted thought. If certain memories are not pleasant, get away from
them by putting the mind on something more sublime. That is why in spiritual
life you are asked to think of God, repeat God’s name even when you are
disturbed by some memory.
To blot out a memory, think of something which is closer to
your heart and soul. . . . Simply telling the mind not to entertain a thought
does not stop it, give it something better, something more divine, something
more precious, and the mind holds on to that.
Keeping the mind on some divine thought, divine name, is of
great spiritual significance; psychologically it helps us a lot; you can avoid
many problems, many difficult situations. Even without an effort on your part,
thoughts come up at different times according to the different suggestions
outside or inside. The only way you can avoid them is to put the mind elsewhere
— the thought that you give the mind must be stronger that the one you want to
avoid, it must draw your entire mind.’
Swami Sarvagatananda (1912 – 2009) of Ramakrishna order
Source - Meditation and its Culmination by Swami Sarvagatananda,
volume one p.158