Replacing Negative Thoughts with Loving Kindness - Jack Kornfield

If you are a person who has regular, repeated thoughts of self-judgment, criticism, shame, or unworthiness, work with this training for a week or, even better, for a month.
First, become more carefully aware of the content and rhythm of the voices inside. What are their regular, unhealthy remarks and devastating comments? What do they sound like? What do they feel like? Begin to study how much pain they cause you. Feel how they take you over and how they hurt. When do they come out most strongly, day or night? What situations provoke them? Social occasions, family time, partners, competitive situations, work or leisure? Do they criticize your body, your mind, your actions, your whole being?
Notice the particular phrases and destructive, unhealthy perspective, the judgment, the shame, the self-denigration they engender.
Now, create a true antidote, a phrase or two or three, that completely transforms the falsehood of these unhealthy thoughts. Let the phrases be the healthiest words you can find, even if you don’t believe them at first. They can be as simple as “Life is precious” or “I will use this day well.” Or they can express the healthy opposite of thoughts of shame: “I will live with nobility and dignity .” Or the opposite of anxiety: “I will live my life with trust.” If helpful, they can be based on the phrases from loving-kindness practice:
May I love myself just as I am.
May I sense my worthiness and well-being.
May I trust this world.
May I hold myself in compassion.
May I meet the suffering and ignorance of others with compassion.
Now begin to work for a week with the phrases you have chosen. Particularly pay attention to those situation that trigger painful patterns. Every time you notice the destructive, unhealthy thoughts, even if they have been playing for a while, pause and feel the pain in them. Take a breath; hold your pain with kindness. The inwardly recite your phrases, firmly, deliberately. Do this over and over. It does not matter if they sound false, if you don’t quite believe them. Say them anyway, out of compassion, as an antidote to your suffering. You may need to say them a thousand times before you realize they are working. And they will.
Like seeds that are being planted, tenderly feel each phrase as if dropping seeds of compassion and care into your mind and body. You can occasionally put a hand on your heart at moments, physically affirming your spirit of kindness, your turn toward well being. Do this for a week, a month, a season. Let these phrases of kindness be planted and slowly, mindfully, notice how the mind and heart can become a source of nourishment and strength.