I went to an elder fellow practitioner's home to visit and found her very pale. When I asked her what was wrong, she said she had recently started to suffer from heart disease.
It turned out that she thought of sending forth righteous thoughts only when her clock struck the hour. She allowed no time to cleanse herself but directly erected her palm to send forth righteous thoughts.
Her third eye can see dimly. One time she began to send forth righteous thoughts five minutes late as compared to the required time. When she sat down, she could see many dark objects. At first she thought that they were Dafa practitioners detained illegally and the dark objects were their heads. This made her feel gloomy and uncomfortable, so she simply moved to a sofa. She still felt the same, so she moved to her bed. The feelings remained the same. From that time on, her heart started to bother her, and she developed a heart problem.
I pointed out that since she did not clean up her own dimension thoroughly during the first five minutes, she was being interfered with. I suggested that she send forth righteous thoughts to eradicate any interference from that old forces imposed on her.
When I saw her again some time later, I found that she had a rosy complexion. It turned out that after I had shared experiences with her, she seriously began to clean up her own dimension. As a result, her "heart problem" disappeared.
In "Teaching the Fa at the 2003 Atlanta Fa Conference," Teacher told us,
"The overall Fa-rectification is destroying evil factors in mass quantities, and Dafa disciples have clarified the truth while validating the Fa, along with this sending righteous thoughts to continually cleanse themselves and clear out the evil in other dimensions, as well as all the other things you've done validating the Fa. All of that is destroying those evil beings and factors that the old forces arranged, and it has had a huge effect."
Here Teacher clearly revealed the importance of sending forth righteous thoughts to cleanse oneself.
In the same lecture, Teacher also said,
"But while cultivating you should have clear awareness, cultivate away your deficiencies, restrain your shortcomings, and eliminate your shortcomings. You must have a sense of constantly climbing up. That's cultivating."
Here Teacher pointed out that clearing out one's shortcomings is necessary for cultivation.
In "Teaching the Fa at the Meeting with Asia-Pacific Students," one student asked,
"Sometimes when I meet with ordeals I don't know if it's a result of my own karma or the old forces' arrangements." Teacher responded, "Regardless of whether it's the old forces' arrangements or karma, we should first of all examine ourselves. I ask you to cleanse yourselves first even when you send righteous thoughts. Look at yourself first, and if you discover that you have a problem, take care of it. With that the old forces won't be able to do anything; when they can't find anything to hold against you they will back off. Of course, at the current time even if the old forces want to back off that doesn't cut it--clear them away entirely. After you cleanse yourself when you sit to send righteous thoughts, clear them away."
This illustrates that cleansing oneself by righteous thoughts is not dispensable but based on Dafa, based on one principle: one must rectify oneself to rectify things outside of oneself. (We should make this demand of ourselves instead of others.) Moreover, looking inwards to clear out one's bad thoughts, karma, and interference will result in more pure effects towards eradicating outward evil.