In fact, the phrase “eternal life” appears 26 times in the New Testament. The phrase “everlasting life” occurs 10 times, and the inverted forms of “life eternal” and “life everlasting” are used 4 times each. This gives us a total of 44 times in the New Testament that God spoke of the eternality of the life that He will give to the righteous. In every single one of those 44 statements, God used the Greek word aionios to convey the idea of eternality. There is not a single reference to eternal life in the New Testament in which God used a different word to convey this idea. This establishes for us that when God uses the word aionios, He intends for it to be a reference to an unending period of time.
Now, let’s turn to Matthew 25. In verse 31 of this passage, Jesus began to teach those around Him about what would happen when He returned to judge the world. He began by saying that the righteous would inherit the kingdom of God, and then He said that the wicked would be cast into a fire, but take a moment to consider His summation given in verse 46:
And these shall go away into everlasting punishment: but the righteous into life eternal.
Here Christ gives us a direct contrast between the punishment of the wicked and the reward of the righteous. The wicked will receive everlasting punishment while the righteous receive eternal life. This seems fairly straightforward in English, but what Greek word do you suppose Jesus used here in reference to the punishment of the wicked? That’s right, He used the word aionios. The exact same word that is used 44 times to speak of the eternality of the life given to the righteous is also used by Christ to speak of the length of the punishment given to the wicked. There can be no doubt that the two are equal in duration. If we know for a fact that the righteous will live forever, then we know with equal certainty that the punishment of the wicked will endure just as long.
Part 2: Other uses of aionios and aion
Part 3: The annihilationist objection