Practicing to develop lovingkindness (metta), warmth, kindness, and love is an ancient vocation. The Buddha’s teachings on metta echo in many ways what we find in Jewish, Christian, Islamic, and other traditions. In this talk, we explore the aims of metta practice, how it works, and some of the different approaches to such practice. With the retreat overlapping with Dr. Martin Luther King’s birthday on January 15, we point to some of the parallels between metta practice and the life and work of Dr. King. We also identify the main challenges of metta practice, including distractions, uneven energy (including sleepiness), inability to access the heart, and difficult emotions, thoughts, and body-states emerging in what we call the “purification” process. As we deepen in metta individually, we also may bring metta into our community, social, and political lives.