Well, first, depending on the language, what you think of as up-to-date translation can be not quite up to date. (The Bible is a huge tome and not frequently r

Well, first, depending on the language, what you think of as up-to-date translation can be not quite up to date. (The Bible is a huge tome and not frequently re-translated. The target language could have changed perceptibly since the latest translation was made.) Let's look at your "modern" example. Now, I'm not a native English speaker, but I strongly doubt any English speaker of today would use "He took his wife." to mean "He accepted her as his wife." It would most likely be interpreted as "He brought along his wife." or "Person A kidnapped person B's wife." And "knew her not"? Very few people speak like that, and even fewer would mean "did not have sex with her". These little details add up much faster than a native speaker may realize. Perhaps more important is the amount of detail that will never show up in the Bible. Read the entire Bible, and I'm sure you'll never learn what "Never mind, I'm OK.", "Nice to see you again.", or "This section is under construction." means. So, you only learn a small fraction of modern language usage, and you learn it in a mostly anachronistic fashion.