What a great question. Here's my short answer:
Salvation is not a thing you get but an interpersonal relationship you enter into with the Author and only Source of Life.
This is an overarching theme of scripture and it's why faith is the only essential to salvation (e.g. Paul in Romans, Jesus in John 3 & 6, etc.). Contrary to claims by detractors like Richard Dawkins,
Biblical faith is not and has never been believing a list of facts without evidence. Instead, Biblical faith is always personal, cooperative trust in the Creator God who discloses his nature (Romans 1:20), His character (Exodus 34:6-7) his mind, will and emotions, (Hebrews 1:1-2).
In Hebrews 11:6, the author explains why faith (i.e. active relational confidence) is vital; in order to please God you have to 1) be convinced that Yahweh is a Person you can know and 2) that your efforts to know Him will bear fruit.
The testimony of scripture affirms God as the only Source and Sustainer of life and and the universe (Genesis 1:1, Psalm, 19, Psalm 139:13, John 1:1-4, Romans 1:20, Hebrews 1:3, Colossians 1:16...). Apart from a connection to Him, no one can exist. I like to picture a fan plugged into a wall; in itself it has no power. Unplugged from the wall it will continue to spin but inevitably will stop, never to continue again until connected to the source of energy. Sin, is rebellion, a rejection of God as the trustworthy Source of goodness, love and life. Hence, sin always results in death and decay, the opposite of who Yahweh is (Matthew 22:32).
In the Gospel (the good news about the Kingdom/Rule of God being re-established on earth - see Mark 1:14), Jesus is the fulfillment of all of Yahweh's promises (Seed of Eve, Seed of Abraham, Lion of Judah, Seed of David) as well as the vindicator of God's faithfulness and compassion along with with his justice (Romans 3:26). Through the blood of Christ, the Lamb of God who takes away sin, we are brought into a New Covenant (Jeremiah 31:31, Hebrews 8:8), a new situation in which God's character (i.e. law) are written internally and in which everyone can interpersonally know God as a Father because we are made alive in the Son (Romans 6, Ephesians 1) through the Holy Spirit. We are now living inside the eternal love/life of the "happy land of the Trinity"(see Fred Sander's helpful book), or as Peter wrote:
"His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature" (2 Peter 1:3-4)
John says it well: "He who has the Son, has life. He who does not have the Son of God, does not have life." (1 John 5:12)
Eternal life is being in God's family by being in the Son. (2 Corinthians 5:17) Born of the Spirit into God's family, we are now able to inherit the same quality of life God enjoy (John 3:5-8, 1 Corinthians 15:42-56)
And that's Good News!