Question: How can we keep impure and undivine thoughts from entering into us?Sri Chinmoy: If you think of purity, impurity cannot come. If you look only at light, light, light, then where is the darkness? But if you stay all the time in darkness and say, "I need light, I need light; where did the light go?" then you are lost. If you go into the room that is dark, you can say, "I need light, I need light," but that does not bring the light; the room is still obscure. But if you stay in the room which is light, then there will be no question of darkness. If you think of purity, then impurity goes away; but if you remain with impurity and cry, "Purity, purity," then you are enjoying one thing and asking for something else. So only stay in purity; just remain in the room that is all illumined. Then you don't have to worry.
Always do the positive thing. By remaining in the negative thing and crying for the positive thing, you won't succeed. Only stay in the positive. When impurity knocks at your heart's door, do not allow it to enter. The problem is that you are not selective. You just keep your heart's door open, and no matter who wants to come in, you allow him. But when impurity comes, if you say, "No! I have kept my door open, true, but it is only for my friends: purity, faith and love," then impurity will leave you.