Thank you for Biblical question on I Peter 1:23, “What is eternal life according to 1 Peter 1:23?”
Eternal life is being regenerated or born again out of an imperishable seed. The means or method of receiving the eternal life is through the Word of God.
The NIV says this, “For you have been born again, not of perishable seed, but of imperishable, through the living and enduring word of God.”
The Greek text says this: “having been regenerated (anagegennmenoi) not by/out (ek) of seed corruptible but incorruptible through (dia) word (the) living of God and remaining.”
Thus one has to ascertain what does one has to believe to be regenerated from the Word of God. Verses 18–21 describes how a person receives this eternal life.
The text says this: “18 For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your ancestors, 19 but with the precious blood of Christ, a lamb without blemish or defect. 20 He was chosen before the creation of the world, but was revealed in these last times for your sake. 21 Through him you believe in God, who raised him from the dead and glorified him, and so your faith and hope are in God” (NIV).
The person believes the words of God that redemption is found in the precious blood of Jesus Christ. It is through his atoning sacrifice that God’s holiness was satisfied whereby God can offer forgiveness to the one who believes in Jesus Christ. Peter concludes that they had received the word that was preached to them (vs. 25b).
John 5 says this, “39 You study the Scriptures diligently because you think that in them you have eternal life. These are the very Scriptures that testify about me, 40 yet you refuse to come to me to have life” (NIV).
Summary: Eternal life can be define as entering into a relationship with God through Jesus Christ to become a child of God. It is more than time, but the quality relationship with God.