Nice change of tense, Jerry. Jesus, here at least, is saying that he "gives" them eternal life, not that He "gave" them eternal life. What kind of eternal life does He give them? Is it a life that has no more death? In a sense, yes, but in a sense, no. In the "no" sense, we expect to die, but we also expect to have eternal life. These two things are antithetical. If one HAS eternal life, then one CAN'T die. Which of those people Jesus was talking about are still alive today? None of them. If we knew where to look, we could see their remains (This was Jesus' argument about David's current state).
So there are two choices: Jesus was talking about the fact that He will raise them from the dead, or He is talking about a different kind of "eternal" life than we are currently experiencing in our physical bodies. Or maybe He's talking about both.
Taking just the first option for a moment, He is saying that He will resurrect them AFTER they die, IF they are His sheep. Here's a larger excerpt:
[Jhn 10:25-29 NIV] 25 Jesus answered, "I did tell you, but you do not believe. The works I do in my Father's name testify about me, 26 but you do not believe because you are not my sheep. 27 My sheep listen to my voice; I know them, and they follow me. 28 I give them eternal life, and they shall never perish; no one will snatch them out of my hand. 29 My Father, who has given them to me, is greater than all; no one can snatch them out of my Father's hand.
The difference Jesus was pointing out between those that were asking if He was really the messiah and those that already believed in Him is exactly that--His sheep already believed in Him. He is not sepcific as to whether their belief was a one-time thing or a life-long thing, but the tense tells us that they [currently, at the moment of Jesus' statement] believe. It also goes further to describe those that will never be snatched out of His hand as those that listen to His voice (remember the detractors were told already that He was the messiah, but they did NOT listen to His voice), and they follow Him, two conditions that surround the words "I know them".
In other conversations of ours, Jerry, you have pointed out that if God KNOWS us, then He knows us all the way through, whether our actions correspond with our faith, or not. I question, along with our brother James, whether it's possible that our actions can really belie our faith, at least over-all (certainly we all have times where we don't follow Christ in our actions, and need to be redirected). But if you are correct in this assertion, then there's no problem for you to consider that God knows whether we will continue to believe for the rest of our lives or not, and thus whether our current state of belief is true.
I don't really know for sure whether God KNOWS what we will do for the rest of our lives or not, thus my somewhat related question earlier in this thread. But I'm pretty certain that if someone is unwilling to obey Jesus's commands to him, if someone is unwilling to listen to His voice, if someone is unwilling to follow Him, that person doesn't seem to fit the criteria for being saved and being with Christ for all eternity. Why would they WANT to be with Christ for all eternity when they would constantly chafe under His authority?
This goes back to the question: What does it mean to believe? remember that Jesus was pointing to belief in God ("believes him who sent me") in this verse rather than belief in Jesus. What does it mean to believe God (not "believe IN God", but "believe God")? It seems like to "believe God" means to accept what He says is true. If someone is not doing that, then they, by definition, DON'T believe God. And if they don't now, then either they have changed their mind about God or they never truly believed God in the first place. Which is it? Does God give eternal life to those that might not really believe?
What does it mean to "come to Christ"? There were quite a few people that "came to Christ" that later turned back (Luke 9:57-62, and):
[Jhn 6:66 NKJV] 66 From that [time] many of His disciples went back and walked with Him no more.
Obviously, those that were His disciples had at one time "come to Him", but now they were no longer "following Him" (they "walked with Him no more"). Is this the same as salvation? Peter thought so: [Jhn 6:68-69 NKJV] 68 But Simon Peter answered Him, "Lord, to whom shall we go? You have the words of eternal life. 69 "Also we have come to believe and know that You are the Christ, the Son of the living God."
Let me explain that I have no desire to suggest to people that God is not able to save those that believe. But there is certainly a class of people that do not believe, and sometimes they disbelieve after at least some indication that they did believe at one point. We should never, in my mind, tell people that because they made a profession of faith at one point in their lives that they are secure for all eternity no matter what they believe now. (No matter what they DO now is another conversation.)
Rather, if anyone
is a believer, he
is assured of his salvation. And if anyone
is not a believer, he
is assured (as far as I know) of his condemnation. We can argue about
how we get to be a believer, but I think my dichotomy is true.