"And these will go away into eternal punishment, but the righteous into eternal life.” - Matt. 25:46
The synonymous Hebrew and Greek words translated as eternal in passages like the above simply mean a long duration or long lasting. Rotherham’s literal translation always translates the words as age abiding. This makes sense. While eternity is a long duration there are other periods of time that are long lasting as well. Being in the belly of a fish for 3 days and 3 nights is a long time. Notice that the passage that describes the time frame of Jonah’s 3 day and 3 night stay in the belly of a fish is the word translated as eternal. The words in Hebrew and Greek simply mean long lasting or a long duration. It doesn’t specify how long. Only that it is a long time period. It doesn’t have to be the same in every instance. The above scripture would be better translated this way:
"And these will go away into long lasting punishment, but the righteous into long lasting life.” - Matt. 25:46
They don’t have to be the same length in each instance. This is especially true because the Greek word for punishment here means correction. This is not everlasting at all.