Jhn 8:35 And the servant abideth not in the house for ever: but the Son abideth ever.
The slave, however, doesn't stay in the family for a lifetime. The son stays for a lifetime.
The "and" in the KJV is actually a "but" or an "however."
The Greek word translated as "abide" is better translated as "stay." It means both "to remain in place" and to "reside at a place." Our word "to stay" has the same feeling.
The concept translated as "for ever" is one of the most problematic ones in the Bible. The KJV consistently translates the Greek word, aion in this way, but its use in ancient Greek is usually more limited. It most commonly means, outside of a Bible, "an age" or "a lifetime."
This raises the question about whether the term "eternal" truly exists in Greek. Did the Greeks think of anything as "eternal"? They certainly had no concept of eternal in the sense of "outside of time" as we think of God as eternal. The Greek gods were "undying," (athanatos), in the sense that they did not age or die of old age. However, in some stories, they were killed and Greek gods certainly existed in time. The forefathers of the gods, the Titans, were defeated by the Olympians and "no longer interacted with the world," which may or may not mean that they were dead.
Some say that the word "aion" comes from aei einai, which means "continual being." Howeve,r "continued being" does not mean "eternal." Other words related to aion, such as the word aidios, which is translated as "everlasting" in the Bible were typically used to mean a period of long, but limited duration. For example, a lifetime stipend is typically described as "aidios". We might describe it as "perpetual" but limited by a lifetime.
δὲ "But" is from de (de), which means "but" and "on the other hand." It is the particle that joins sentences in an adversarial way but can also be a weak connective ("and") and explanation of cause ("so") and a condition ("if").
οὐ "Not" is from οὐ ou which is the negative adverb for facts and statements, negating both single words and sentences. The other negative adverb, μή applies to will and thought; οὐ denies, μή rejects; οὐ is absolute, μή relative; οὐ objective, μή subjective.
εἰς "For" is from eis (eis), which means "into (of place)," "up to (of time)", "until (of time)", "as much as (of measure or limit)", "as far as (of measure or limit)", "towards (to express relation)", "in regard to (to express relation)", "of an end or limit," and "for (of purpose or object)."
εἰς Untranslated is eis (eis), which means "into (of place)," "up to (of time)", "until (of time)", "as much as (of measure or limit)", "as far as (of measure or limit)", "towards (to express relation)", "in regard to (to express relation)", "of an end or limit," and "for (of purpose or object).