The doctrine of the divine simplicity is a classic understanding of the Christian God, along with the doctrine of the Trinity. However, some modern theologians have difficulty in accepting that the doctrine of divine simplicity is a Christian understanding of God. They argue that not only is this doctrine illogical, but it also originated from Greek philosophy and has no biblical evidence. In response to these modern critics, this paper assesses Hilary’s doctrine of divine simplicity, arguing that as a pro- Nicene theologian, he taught the doctrine of divine simplicity, which he believed was rooted in Scripture. For the bishop, divine simplicity was a basic language to describe the nature of the triune God. This paper is divided into three parts: the first section offers Hilary’s theological method; the second section offers the bishop’s exegetical foundation of the doctrine of divine simplicity; and the third section presents Hilary’s use of divine simplicity in his theology of God. This paper aims to make two contributions: first, as a part of the Evangelical ressourcement project, which seeks to retrieve the teachings of the church fathers, to demonstrate their common understanding of the doctrine of divine simplicity, which is deeply rooted in Scripture; and second, to contribute to Hilary’s modern scholarship through the study of his works on the doctrine of divine simplicity.