One way to develop metta within us is through the following meditation practice, which we start by extending loving feelings toward ourselves.
It’s very simple: At first, sit in some comfortable position, and keeping an image or felt sense of yourself in mind, slowly repeat phrases of lovingkindness for yourself: May I be happy, may I be peaceful, may I be free of suffering. Say these or like phrases over and over again. We do this not as an affirmation, but as an expression of a caring intention. As you repeat the words, focus the mind on this intention of kindness; it slowly grows into a powerful force in our lives.
Although the practice is straightforward, it can be extremely difficult. As you turn your attention inward and send loving wishes toward yourself, you may see a considerable amount of self-judgment or feelings of unworthiness. At these times, proceed gently, as if you were holding a young child. A line from an old Japanese samurai poem expresses well this part of the practice: “I make my mind my friend.”
–Joseph Goldstein, from “Triumph of the Heart,” Tricycle, Spring 2008