Eternal or Unending life
Eternal - Everlasting or Unending life
When people speak about "Eternal life" for mankind they mostly mean "everlasting life" or a life without an end or "unending life", because "eternal means normally no beginning and no end, like God Who had no beginning (no birth) and no end (no death).
Eternal could also mean perpetual or continued without intermission, but the majority of people shall have their life interrupted by death, where there shall be no feeling, it being like a deep sleep.
The world know about"the Christian promise of eternal life "
God has given the free Gift of "unending life" for those who are willing to accept the son of God, who paid the ransom price for the sins of man.
In John 17 v 1 to 5 Jesus prays that people will know that God’s plan to give eternal life involves recognising that he is sent by God
“1 After Jesus said this, he looked towards heaven and prayed: "Father, the time has come. Glorify your Son, that your Son may glorify you. 2 For you granted him authority over all people that he might give eternal life to all those you have given him. 3 Now this is eternal life: that they may know you, the only true God, and Jesus Christ, whom you have sent. 4 I have brought you glory on earth by completing the work you gave me to do. 5 And now, Father, glorify me in your presence with the glory I had with you before the world began.” (Joh 17:1-5 NIV)
A selection of verses showing that we cannot earn salvation, it is given freely by God
Jesus makes it clear that eternal life is a gift from a loving God:
John 3 verse 16:16:
For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life.
Paul tells us that death is a result of our sins, but by grace we can receive the gift of eternal life though Jesus:
Romans 5 verse 15:15:
But the free gift isn’t like the trespass. For if by the trespass of the one the many died, much more did the grace of God, and the gift by the grace of the one man, Jesus Christ, abound to the many.
Romans 6 verse 23:23:
For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.
Ultimately it is faith that leads to eternal life:
Galatians 3 verse 22:
22 But the Scripture imprisoned all things under sin, that the promise by faith in Jesus Christ might be given to those who believe.