Interestingly, these are the name of God, and the name of his son, yet neither of these words appears in most modern English Bibles.
Why not?

Let’s look at them one at a time. But before we do, let’s look at the letter “J”.
J came into English around a thousand years ago, and it replaced the letter I at the beginning of some words. But unlike the way we say it today, at that time it had a Y sound. So Joshua was pronounced more like Yoshua. Keep that in mind. It might help later.

Now, in the Old Testament God has a name. His name is יהוה‎ which we usually write in English as Yahweh.
Written Hebrew doesn’t have vowels. The reader is supposed to work them out as they read. Which if you practise is not usually difficult. Wht ds ths sy? (What does this say?).
So more literally, the Hebrew name for God in English is YHWH. But we don’t usually interpret vowels as we read in English, so it is easier to communicate if we put them in. So we write Yahweh.

In some older English Bibles they wrote this as Jehovah. Remember the J thing? So that would have read more like Yehovah. Now I’m sure you can see where that came from. And now you know why it has a J.
So, God’s name is Yahweh. But you don’t see that in many translations.

We’re not sure exactly when, or who did it, but we think that a bit before 100BC a group of seventy scholars translated the Jewish scriptures, (pretty much what we have as our Old Testament), into Greek. This translation is called the Septuagint, and its abbreviated name is LXX, which is 70 in Roman numerals.
Wherever the name Yahweh appeared in the Hebrew scriptures, the LXX translators used the Greek word κυριος (kurios), which means lord or master.
So, when the translators wrote the King James Version in the 1600’s they continued this practice, and wherever the Old Testament used the name Yahweh, they translated is as Lord. Then, to distinguish it from places where the Hebrew actually did say Lord, they capitalised it. And most modern English translations copied that and they usually write it like this - LORD.

God has a name. In English his name is Yahweh. But in most English Bibles it has been replaced with LORD. About 7,000 times!
So whenever you read LORD in your Bible, think Yahweh.

Why? Well... I have a theory.

I presume you know the 10 commandments right? (BTW: I presume you also know that they are for Jews, not for Christians right? If not, you had better read these articles sometime Rules For Christian Living and The New Covenant Replaces The Old One).
The third commandment says, “You will not misuse the name of Yahweh your god.”
Now, as time went on from there, the Jews became more and more legalistic about all their rules. To the point that they even concluded that Jesus was not God’s son because he healed someone on a Sabbath. And they had decided that nobody was allowed to do anything on a Sabbath. And they had made up more rules about having to wash bowls in certain ways before you could eat from them.
So I believe that in their legalism they were so afraid of misusing the name of God that they stopped using it altogether. So they never say God’s name. And if they have to write it they would write Lord instead. Many modern Jews will write G*d to avoid using his name.
Yahweh didn’t say not to use his name. He said not to misuse his name. This is clearly a legalistic overreaction.
Now, we’re Christians, so the ten commandments doesn’t even apply to us. And even though we can still use them as guidelines to understand what right behaviour is, we don’t have to be so legalistic. (In my view it almost verges on superstition). So let’s go back to using God’s name. Let’s be proud to be known as Yahweh’s people.

Jesus has a name too. And it’s not Jesus!

The New Testament documents are pretty much all written in Greek. In those documents Jesus is called Ιησους (Iesous). Later on the church decided to do everything in Latin. So it became IESUS in Latin. And then later, it became Iesus in English.
Remember the J thing? So about a thousand years ago the I was replaced with a J and it became Jesus, (but it was still pronounced Yesus). And now in modern English we usually call him Jesus. Even though that is a long way from his real name. (But you can see how we got there).

So what was his name?
Ιησους was the Greek way of writing the Hebrew name יְהוֹשֻׁעַ (Yeshua), which we usually write as Joshua in modern English. (Remember the J thing?). Jesus’ name was Yeshua. It still is.
Now, if you read Acts 7:45 and Hebrews 4:8 in an English Bible you will almost certainly see the name Joshua. These are all referring to the Old Testament Joshua, who was Moses’ assistant until Moses died, and who led the Israelites into the promised land.
But his Greek name is the same, Ιησους (Iesous). So to differentiate him from the son of God the translators chose to translate his name as Joshua and the son of God’s name as the Latin derived name Jesus.
Personally I don’t think that is helpful. I can see how it came about, but it is an inconsistent translation, and it hides something wonderful.
Both their names were Yeshua. God chose that name. And he had a reason for doing that.

Yeshua means “Yahweh Saves”. That’s a pretty powerful name. And there are a lot of parallels between the Old Testament Yeshua leading his people into the promised land, and the New Testament Yeshua leading his people into eternal life.
Perhaps God did that deliberately?

I don’t think this is just an intellectual exercise. It is interesting to know how these things came about, but what does that mean for us on a practical level?
I think it’s time to repair the damage. It’s going to be a hard habit to break, but I think we should stop using the name Jesus and call him Yeshua. And we should start calling God by his name, Yahweh.

When Hilkiah the priest found the Book of the Law in the temple, (2 Kings 22), king Josiah realised that they had not been living according to the words in the book. So they changed their ways. These would have been dramatic, major, lifestyle changes, but they made them anyway - simply because they realised they were not doing things the way Yahweh had commanded.
Changing our habits to use the names Yahweh and Yeshua might not be easy, or convenient, or comfortable. But if it is the right thing to do then it is the right thing to do.