Passage
and life age-during I give to them, and they shall not perish--to the age, and no one shall pluck them out of my hand;
and life age-during I give to them, and they shall not perish--to the age, and no one shall pluck them out of my hand;
John 10:26 but ye do not believe, for ye are not of my sheep,
John 10:27 according as I said to you: My sheep my voice do hear, and I know them, and they follow me,
John 10:28 and life age-during I give to them, and they shall not perish--to the age, and no one shall pluck them out of my hand;
John 10:29 my Father, who hath given to me, is greater than all, and no one is able to pluck out of the hand of my Father;
John 10:30 I and the Father are one.'
The verse centers on "life", "age-during", "give", "shall", "perish--to", "pluck", and "hand". It is saying that the verse draws attention to "life" and "age-during", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 27's "according as I said to you My..." into verse 29's "my Father who hath given to me...", so "life" and "age-during" belong inside that flow. In John context, the local focus is the identity of Jesus, new birth, eternal life, and belief and unbelief.
A plain takeaway is to answer the verse's own emphasis on "life" and "age-during" with trust shaped by these words, not by a vague optimism outside the passage.