The theological debate between Pelagius and Augustine concerning the doctrine of salvation (soteriology) is one of the most fundamental discussions in the history of the church and remains relevant to the present day. This article critically examines the fundamental differences between Pelagius’s thought, which emphasizes human free will and moral responsibility, and Augustine’s view, which affirms God’s grace as the sole foundation of salvation. Using a qualitative research method through a literature review and a systematic-theological analysis, this study explores the intellectual foundations of both figures, the biblical foundations of soteriology, and their relevance to the understanding of salvation in the 1996 HKBP Confession. The findings indicate that the debate centers on three major issues: (1) the doctrine of original sin, (2) the role of free will in salvation, and (3) the nature of God’s grace. Augustine asserts that humanity is entirely dependent on God’s grace because of the total corruption caused by sin, whereas Pelagius views human beings as possessing the moral capacity to choose what is good without determinative divine intervention. The 1996 HKBP Confession clearly aligns itself with the Augustinian perspective by emphasizing salvation as the work of God alone through faith. This study concludes that a balanced understanding of soteriology has practical implications for church life, particularly in shaping a grace-centered spirituality, encouraging authentic faith development, and fostering a responsive ministry ethic without falling into either legalism or antinomianism.