It is very often said that the word "personality" is derived from Latin "persona" meaning "mask" put on by the actor at the ancient Roman theater. And most ethical theories have so far interpreted personality in this way. I should like to assert in this paper that the word "personality" originates in Hebrew "panim" (face) in the Old Testament. Ancient Hebrews did not know the philosophical concepts which ancient Greeks were very familiar with. In order to denote God, the Hebrew writers of the Old Testament used personified expression including the metaphor "the face of God." It means the presence of God; in other words, God's participation in Israel's history. Several phrases had been made in order to express either God's grace toward Israel or His judgment against Israel. They are also metaphorical expressions of the personal relations between God and man. Those usages of "face" were succeeded by the Greek New Testament through the medium of the Septuagint which is the translation of the Old Testament from Hebrew into Greek. What is more, Martin Buber's personalistic interpretation of the Old Testament is one of modern philosophies emphasizing the meaning of the word "personality."