We trust God to keep His promises. You should to.
But he has not get given that eternal life.
As he explained to Nicodemus it can only come in a new, immortal body.
As usual, you appear to be trying to make a specific condition out of a generality.
Yeshua himself said in Matthew 24 that only those that endure to the end shall be saved. So while no one can pluck us out of his hand, we are free to leave his hand by our own volition. Paul and Peter explained this fact in great detail in Hebrews 6, and 2Peter 2.
It just requires a less tendentious mode of reading, so that one gets God’s meaning rather than one’s own desire.
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