The Scripture teaches that death is not the end of existence. The Bible says that the spirit, or soul, of humans will exist forever. This brings up the issue of immortality. If human beings are going to live forever, does this mean they are immortal? If humans are immortal, then in what sense do they have immortality?
God Alone
Immortality means not subject to death. The Bible says God alone has immortality.
Who alone has immortality, dwelling in unapproachable light, whom no person has seen or can see (1 Timothy 6:16)
In this passage we see that immortality is something that is part and parcel with the nature of God. He alone has it. The Scripture teaches that only God has life in Himself.
For as the Father has life in Himself, so He has granted the Son to have life in Himself (John 5:26).
Only God is deathless in His essence. He alone is immortal in this sense of the term.
Imparted By God
Yet the Bible says that immortality is something that God imparts to believers. The Old Testament taught that immortality would result by living righteously before God.
In the way of righteousness there is life; along that path is immortality (Proverbs 12:28).
New Testament Teaching
The New Testament also says that God grants immortality to humans who trust in Him.
So when this corruptible has but on incorruption, and this mortal has put on immortality, then shall be brought to pass the saying that is written: 'Death is swallowed up in victory' (1 Corinthians 15:53,54).
From this passage we discover three things about immortality.
1. Immortality is given only to believers, there is no mention of unbelievers receiving it. Therefore it is more than endless existence.
2. It is a gift from God that believers will receive in the future at Christ's coming.
3. Immortality refers not only to the soul or spirit, but the body is also included. Believers become immortal when this mortal body puts on an immortal one.
Brought By Christ
God the Son, Jesus Christ, brought immortality to the believer.
but it has now been revealed through the appearing of our Savior, Christ Jesus, who has destroyed death and has brought life and immortality to light through the gospel (2 Timothy 1:10).
Not Immortal By Nature
Therefore, according to the Bible, humanity is not immortal by nature. The human soul, or spirit, survives death, but the body does not. Immortality is achieved when the body of the believer is raised and transformed and then united with the soul.
Immortal Inheritance
Christians have an immortal inheritance awaiting them.
Blessed be the God and Father of our Lord Jesus Christ! By His great mercy He has given us a new birth into a living hope through the resurrection of Jesus Christ from the dead, and into an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you (1 Peter 1:3,4).
Not The Same Thing As Resurrection
Immortality is not the same thing as resurrection. Immortality occurs at the resurrection when the believer receives a new body from the Lord.
Not The Same As Eternal Life
Immortality is not the same as eternal life. Believers receive eternal life the moment they trust Christ.
And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent (John 17:3).
Eternal life consists of a relationship with a person - Jesus Christ.
Differences
We can sum up the difference between the immortality of God and of humans as follows. Immortality is basic to the nature of God, not humanity. God is immortal, those humans who believe God's promises have immortality. God is immortal in His essence, believers have a derived immortality. God had no beginning or end. Believing humans had a beginning but will have no end.
What About Unbelievers?
If only believers have immortality, what can we conclude about the state of unbelievers? Scripture says that unbelievers will exist forever, but they will exist apart from the life of God. They do not have immortality in the biblical sense. Immortality consists of eternal life in Jesus Christ. Unbelievers have no such life, so they are not immortal according to the biblical understanding of the term.
Summary
Only God is immortal, or deathless, by nature. The Lord, however, imparts immortality to those who believe in Jesus. At His coming, believers will receive a glorified, immortal body that will be united with their spirit. Immortality is not the same as eternal life. Eternal life is received the moment a person trusts Christ, while immortality occurs at the resurrection of the body. Although unbelievers will exist forever, they are cut off from the life of God, and do not have immortality in the biblical sense. According to the Bible, immortality is more than eternal existence.