Sejong Lee with the pen name “Yi-gong” is an honored man who is considered a saint by Korean Protestantism. With the life of Yigong, the researcher finds it implying a vital message that is fundamental to today’s social welfare practitioners. By examining Yigong’s life, this study investigates, first and foremost, the relationship with the ultimate being and the establishment of eco identity as the existential foundation of Social Welfare. Following the first point, the study explores the world view of spiritual social work that takes the apocalyptic perspective to the world, breaks out of, and re-enters the world. Furthermore, the study understands of the true ground and purpose of the social welfare practice by analyzing the altruistic, spiritual, and existential value system that could be learned from Yigong’s life. Therefore and lastly provides direction to the principle and practice as self-sacrifice, empowerment, reconstruction of perception, subjectivation of self, taking the initiative, and self-determination.