The Hebrew emun (אֵמוּן) means faithfulness, reliability, or steady trustworthiness. It is cognate with aman (H539, to trust/believe) and emunah (H530, faithfulness), all rooted in the concept of stability and firmness. Emun describes the consistent, unwavering character of one who keeps their word. The term appears rarely but at important junctures, particularly in the Psalms describing God's character.
The faithfulness described by emun is central to Israel's understanding of God. Unlike the capricious gods of surrounding nations, Yahweh is characterized by absolute reliability — His promises are sure, His covenant stands. Deuteronomy 32:4 calls God "a God of faithfulness [emun] and without iniquity, just and upright is he." This divine faithfulness becomes the ground of human trust. The New Testament concept of pistis (faith/faithfulness) builds on this foundation — true faith is a response to a faithful God.