Echad means one, single, first, or united. Appearing over 900 times, its use in key theological passages — especially the Shema — has made it one of the most theologically debated Hebrew words in both Jewish and Christian tradition.
In Deuteronomy 6:4, 'The LORD our God, the LORD is echad,' this word affirms God's unique oneness. Christian theologians note that echad can express compound unity (as in Genesis 2:24 — 'the two shall become one flesh'), consistent with Trinitarian theology. Jewish interpreters emphasize its affirmation of absolute monotheism.