Rabbi Nachman teaches,
Man’s mind is his very essence. Wherever your thoughts are, that is where you are – all of you.
This is why it is so important to avoid all evil thoughts, because otherwise that is where your place will be.
You must force yourself to think good thoughts in order to be worthy of know ing G-d. Then your place will be with Him and you will be merged with Him. The greater your perception of G-d, the more fully merged with Him you will become, and then you will attain eternal life.
Likutey Moharan I, 21
With permission taken over from: Daily Dose Of Rabbi Nachman
