This was so that just as sin ruled [over mankind], causing [physical] death, even so God's unearned favor would rule [over mankind], providing [them with] righteousness, and leading to never ending life through Jesus Christ our Lord.
Yet [physical] death ruled [over mankind] from the time of Adam to Moses, even over those people who had not sinned the way Adam did. [Now] Adam prefigured the coming of Jesus.
For we have all received from His full richness one favor after another.
Therefore, just as sin came into the world through [the action of] one man [i.e., Adam] and [physical] death through that sin, so [physical] death has spread to all people, because all people have sinned. [Note: This difficult passage (verses 12-21) seems to be saying that the entire human race must experience physical death because of Adam's sin (I Cor. 5:22), which is somehow considered to be everyone's sin. See Murray, pp. 180-187, for a thorough discussion].
For the wages for sinning is [spiritual] death, but God's free gift is never ending life in [fellowship with] Christ Jesus our Lord.
For God's unearned favor has appeared, bringing salvation to all people [i.e., in the coming of Christ].
I give them never ending life and they will never be destroyed, and no one will [be able to] steal them out of my hand.
For it was not through [obedience to] law [See 3:31] that the promise to Abraham or his descendants of inheriting [the best of] the world [was made], but through their being considered righteous because of faith [in God].
For if [physical] death ruled [over mankind] because of the sin of the one man [i.e., Adam], how much more will those who receive the abundance of God's unearned favor, and the gift of being right with Him, rule in [never ending] life through the one man, Jesus Christ.
So, do not allow [the practice of] sin to rule your mortal bodies, so that you obey its desires.
For sin must not be your master [i.e., it must not have power over you], for you are not governed by law, but by God's unearned favor.
Do you not know that you are the slaves of whoever you offer your obedience to? If you obey [the desire to] sin, it leads to [spiritual] death; or if you obey [God] it leads to righteousness.
And if Christ lives in your hearts, even though the body is [doomed to] death because of [Adam's ?] sin; yet the spirit is [destined to] live [forever] because of being [made] right with God. [Note: Some take "spirit" here to be "Spirit" and make it "The Holy Spirit gives you life." See next verse].
So, we should approach, with confidence, God's throne of unearned favor, so we can receive mercy and obtain that favor to help us when we need it.
And the God who bestows every unearned favor [upon His people], who invited you to partake of His eternal splendor through Christ Jesus, will restore, confirm, strengthen and stabilize you people [in the faith], after you have gone through a brief time of suffering.
[This letter is being written by] Simon Peter, a slave and apostle of Jesus Christ, to those who have received a faith just as precious as ours, through the righteousness of our God and Savior Jesus Christ.
And this is the promise which Christ [or, "God"] has given to us: [It is] never ending life. [Note: This passage may mean that God promised us "the Eternal Life," that is, Christ, See John 3:16].
And this is the testimony [of God]: He gave to us [the hope of] never ending life, and this life is [available through fellowship] in His Son.