What’s the difference between Yahweh and Jehovah? Also, why is LORD sometimes in all capital letters?
This name for God is how God introduces Himself to Moses. It’s not a generic term for a god, it’s the proper name He chose for His covenant relationship with Israel.
Exodus 3:13,14 Then Moses said to God, “If I come to the people of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ what shall I say to them?” God said to Moses, “I am who I am.”
It’s related to the Hebrew verb “to be”, so in this very name, we can be assured that God is right here, available to us no matter our need, ready to guide us and to forgive us.
Ancient Hebrew was written only in consonants, so the original pronunciation is debatable. The letters in Hebrew, יהוה, are YHWH when transliterated into latin letters. Theologians call this the tetragrammaton, the four letters that represent God's proper name. When reading aloud or even silently to themselves, Hebrews would substitute the word adonai, which means master, to avoid misusing God’s name. Later on, scribes inserted the vowels of adonai into the name, which became YaHoWaH. Thus, early Bible translators made the mistake of translating God’s name as Jehovah.
Today, most scholars think the most natural and accurate pronunciation is really Yahweh. In most cases, Bible publishers today use the capitalized name LORD, sticking with the Hebrew tradition of honoring God’s name by substituting a word for master, rather than writing Yahweh.