Yahweh is an Anglicized version of the Name of God, as spoken during the time of the Temple and understood by Judaism and Christianity as taught in the Old Testament or the Bible. In the Hebrew written language, which often uses no written vowels, The Name is written YHWH, but never spoken.
However, because Jews generally were forbidden by the Third Commandment to pronounce the sacred name, the vowels of Adonai (literally 'my lords') were normally inserted between its consonants, resulting in the name 'Jehovah'. Reflecting the same taboo, the earlier English translations of the Bible replaced the name with the phrase 'the LORD'. Because Jesus' followers routinely called him adon ('boss', 'lord', which translated into the gospels' Greek as kurios), the two titles became confused in English, to the point where it became unclear whether the phrase 'the LORD' was referring to Jesus or to Yahweh.
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