Remember, in English and in Hebrew, the word “God” (or El, or Elohim) is not a name, but a generic title for a deity that could be applied to other, lesser, spiritual beings. Neither the ancient Israelites, Jesus, nor the early Christians believed that their God was the only spiritual being that existed. There were many such beings who were lesser than the one true God because they were created, not the Creator. But they were real beings nonetheless, and so they are called “Elohim,” or “gods” in the Old Testament (see some examples in Genesis 35:2; Joshua 24:2; Psalm 136:2). For example, to the north of Israel lived the ancient Syrians, and their chief god was called “Baal” (familiar from the stories about Elijah, see 1 Kings 18), or the Moabites to the east worshipped Chemosh (see 1 Kings 11). Yet, the Israelites were unique, in that they gave their allegiance to a deity that was not named or worshipped anywhere else in the ancient world. This God’s name was “Yahweh” (perhaps originally “Yahuwah”). The name was first revealed to Moses according to Exodus 3:12-15, and the stories about Abraham in Genesis make it clear that this was the God Abraham related to as “El” or “El-Elyon,” and so on. The name means “He will be,” which will spin your brain a bit. It’s a fitting name for the eternal Creator of all things, a profound statement that this God is the ultimate author of all reality, the one without beginning or end.
Much later in Israel’s history (around the 3rd or 2nd century BC), people stopped pronouncing Yahweh’s name aloud, likely as a form of reverence. So, when they came across the letters for “Yahweh” in the Bible, they would not say “Yahweh,” but replace it with the Hebrew word for “Lord,” pronounced adonai. Much later, in the 6th and 7th centuries AD, Jewish scribes made a really cool manuscript reminder for readers to not pronounce the name. They left the letters of Yahweh’s name in the biblical text (YHWH), but inserted the vowel sounds of the word “Lord,” or adonai. The result in the Hebrew text was a hybrid word yehovah, that corresponded to no actual Hebrew word that any Israelite ever said aloud. The irony, of course, is that later European Christians who tried to learn Hebrew didn’t know this wasn’t the real, divine name, and so the name “Jehovah” entered Christian history and has remained ever since.