Benzoic:
Why do you suppose God chose to use a subjunctive for apollumi and echo? Why not use a indicative?
I'm not sure that God chose to use a subjunctive, but John the apostle used it, probably because it is correct grammar, and the King James translators used an English subjunctive for the same reason. This question is simply a grammatical question.
Many modern people omit the subjunctive mood altogether in their speech and writing, and substitute a simple future in the indicative. But the subjunctive mood was used up to about 1950 or so. It is difficult to find a grammar book which deals at any length with the subjunctive in English. Many people are not even aware that it exists, and I myself have only partial knowledge of the English forms of the subjuntive.
The fact that "may" and "might" have both a subjunctive use and a non-subjuctive meaning further confuses the matter. Consider this conversation between John and Joe:
John notices Joe heating iron in the physics lab.
John: Joe, why are you heating that piece of iron?
Joe: I am heating it so that it may expand.
John:
May expand? There's no "may" about it. If you heat it, it
will expand!
Joe: John! After "so that" one uses the subjunctive mood in English. It is grammatically incorrect to say, "I'm heating the metal so that it will expand." When you object to my using "may", you are thinking of the "possibility
may". I was using the "subjunctive
may.
Examples:
1. Possibility "may"
Sam said, "I may go to town today."
Sam is not sure whether or not he'll go to town today. He hasn't decided yet.
2. Possibility "might"
Much the same meaning.
Sam said, "I might go to town today."
3. Subjunctive "may"
I am studying hard so that I may pass the exam.
Often the main clause (in the case "I am studying hard") states a necessary condition in order that the statement of the other clause "I may pass the exam" may come to be true.
Sometimes when the subjuctive is used after "that" or "so that", when the condition stated in the main clause is not a necessary condition.
Sometimes the statement of the main clause is both a necessary and sufficient condition in order that the statement in the other clause come to be true. An example of this would be the one mentioned above concerning the heating of the iron. It is necessary to heat iron so that it may expand, and it is a sufficient condition to make it expand.
The use of the subjunctive in itself does not indicate whether the main clause describes a necessary condition, or both an necessary and sufficient condition, or neither.
4. Subjunctive "might"
John proposed to Xenia so that she might marry him.
This is not the "possibility
might" This is not a statment that Xenia might marry John, or she might not. Rather it is the "subjuctive
might".
God ... sent His only-begotten Son that whoever believes in him might not perish but have aeonian life.
Again this is not the "possibility might". If John has meant that he would have written something like, "God sent His only-begotten Son. Whoever believes in Him might not perish but have aeonian life." That would be a completely different meaning.
The King James uses "should not perish", another form of the subjunctive. It means the same as "might not perish" when used in the subjunctive mood.
We Christians believe that the sending of God's Son coupled with our believing in Him (I know there is disagreement about what "believing in Him" means --- but that's another issue we won't discuss right now), is a necessary and sufficient condition for having aeonian life. We know it is not a "possibility
might" that is being used here, but a "subjunctive
might". The subjunctive mood is a grammatical matter and is unrelated to how certain the truth of the second clause is, if the stated condition of the main clause if fulfilled.