Those who live by faith in Jesus Christ do so trusting in (to use the words the apostle Peter), “precious and magnificent promises.” (2 Pet. 1:4) Chief among God’s wonderful promises are, “The hope of eternal life, which God, who cannot lie, promised long ages ago” (Titus 1:4).
Three times the apostle Paul calls this promised salvation a “free gift,” saying, “For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord” (Rom. 6:23), contrasting the woeful effects of sin with the great gift of God.
Though this is a free gift, it’s not at all a cheap, temporary or low-quality one.
In quantity or duration, this gift is without end, so we call it “everlasting” (as in the King James and NKJV translations) or “eternal” in the most other translations. So John 6:40 says, “For this is the will of My Father, that everyone who beholds the Son and believes in Him, may have eternal [or everlasting] life; and I Myself will raise him up on the last day.”
This gift is also of surpassing quality. Jesus said, “…I came that they might have life, and might have it abundantly.” (John 10:10) So John spoke of Christ bringing and giving this eternal life, and the blessings leading to it, saying, “For of His fulness we have all received, and grace upon grace.” (John 1:16)
So we live by this hope, as John the Apostle simply stated: “This is the promise which He Himself made to us: eternal life.” (1 Jn 2:25)