Question: "Why is Joshua called "Jesus" in Hebrews 4:8 in the KJV?"
Answer: In the King James Version, Hebrews 4:8 says, “For if Jesus had given them rest, then would he not afterward have spoken of another day” (emphasis added).
In the New International Version, the same verse says, “For if Joshua had given them rest, God would not have spoken later about another day” (emphasis added). Most other English translations of this verse also refer to Joshua and not Jesus.
Hebrews 4:8 is obviously referring to the Old Testament character of Joshua, the son of Nun. The previous verses had been speaking of Moses and the wilderness wanderings and the Israelites’ entering of the Promised Land (Hebrews 3:16–19). Despite the passage’s being about Joshua, the KJV uses the name Jesus.
But Hebrews 4:8 is not the only New Testament passage in which Joshua is called “Jesus” in the KJV. In Acts 7:45, Stephen speaks of his “ancestors under Joshua” bringing the tabernacle into the Promised Land (NIV, ESV, NKJV, NASB, et al., emphasis added). According to the wording of the KJV, however, the tabernacle was “brought in with Jesus” (emphasis added).
So, what explains the name switch? Why does the KJV say “Jesus” in the New Testament instead of “Joshua,” when it’s clearly the Old Testament leader Joshua in view?
The answer is that Jesus and Joshua are really the same name, although in different languages. The Greek form (in English) is Jesus. The Hebrew form (in English) is Joshua. Both forms of the name mean “The Lord Is Salvation.”
In the Old Testament Hebrew, Joshua’s name is יְהוֹשׁוּעַ or, transliterated into English, Yehoshua, a form of Yeshua. This is where we get the English name Joshua. But, when the Hebrew name is translated into Koine Greek, the original language of the New Testament, it becomes Ἰησοῦς, which transliterates into Iēsous. And this is where we get the English name Jesus. Thus, Yeshua and, correspondingly, Joshua and Jesus all mean “Yahweh Saves” or “The Lord Is Salvation.”
The same type of linguistic metamorphosis occurs today among names. For example, a man with the Spanish name Jorge can choose to go by the English form of his name, George. Both Jorge and George are the same name but in different languages. If Jorge were to travel the world, then his name might become Giorgio, Yuri, Jurgen, Juris, Jerzy, Gorka, or Seòras, depending on the country he was visiting. Regardless of the form his name takes, he’s still the same person. In the same manner, the Old Testament Joshua remains the same person, even if called by his Greek name, Jesus.
For some reason, the translators of the King James Version chose the Greek form of Joshua’s name, Jesus, which causes a little confusion in Hebrews 4, since the author of Hebrews is contrasting Jesus with Joshua in that chapter. Other translators have chosen the Hebrew form, Joshua, which helps us know who is who. The Old Testament Joshua led God’s people into the Promised Land, giving them a temporary, physical rest, but only Jesus can give us a permanent, complete, and spiritual rest.