ESV - 8 For by grace you have been saved through faith. And this is not your own doing; it is the gift of God.
In Eph 2:8 the gift is salvation, by grace and through faith. The process of salvation is taken as a whole in regards to source, reason, and mechanism. Paul contrasts salvation by grace and through faith with 'works', for man cannot achieve salvation by his own merit. ("Faith" & "grace" are in the feminine gender, but "this" & "gift" are in the neuter gender. In Greek, this then applies the 'gift' to the entire clause.) It's a similar train of thought to Rom 5:18-21. While we were all condemned by the law and sin reigned, the death of Christ brought justification by His own blood. In this grace reigns (the 'by'), through righteousness and through Jesus (the process), to bring eternal life (the 'what'). The process is given in even more detail in Rom 3:22-26: Righteousness is given through faith to all who believe. We are justified by grace, through the redemption that is in Christ Jesus. God displayed Christ publicly (grace) as a propitiation (atoning sacrifice) whose blood is applied to us through faith. These and other similar passages are summaries of the gospel; that while we were yet sinners, Christ died for us. We receive Him by faith and are justified, receiving the righteousness of Christ in place of our own sins, and will never perish but will have eternal life. (Tit 3:3-8, Heb 10:22, II Tim 1:9-11, 2 Corinthians 5:21) We only have the offer of salvation because of grace. Because we could not save ourselves, God the Father in his mercy and grace sent His only begotten Son to die for the ungodly as propitiation, an atoning sacrifice, on behalf of our sins. (Rom 3:25, Rom 5:6-8, Rom 5:15-17, John 12:32, John 3:14-17). Salvation is by grace (Rom 11:6), not works, so that man can never boast. (Rom 6:19-23, Eph 2:8-9, Is 63:4-5, Rom 8:1-4, Acts 13:39, Phil 3:7-9, etc.) How great a salvation is this! It does not come by our merit, but by God's grace. It does not come through our dead works, but through our belief in the Messiah (John 6:28-29, John 3:16). It is a salvation beyond the capacity of man to achieve or offer. "But the gift is not like the trespass. For if the many died by the trespass of the one man, how much more did God’s grace and the gift that came by the grace of the one man, Jesus Christ, overflow to the many!" Rom 5:15 "But when the kindness and love of God our Savior appeared, He saved us, not because of righteous things we had done, but because of his mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit, whom he poured out on us generously through Jesus Christ our Savior, so that, having been justified by his grace, we might become heirs having the hope of eternal life." Tit 3:4-7 Salvation is through faith; more specifically, through faith in the person and work of Christ who died for our sins. It is through faith that we are justified (Rom 5:1, Rom 3:24-30); through faith that we enter the covenant with Christ; through faith we are reconciled to God and may approach Him (Rom 5:1-11, Eph 3:12); through faith that we have access into the peculiar grace a believer stands in (Rom 5:2); through faith we are raised with Christ and receive the righteousness of Christ imputed to us (Col 2:11-13, Rom 6:4, Rom 3:22, Phil 3:9, Acts 13:39); through faith we are shielded by God's power until the coming of salvation (I Pet 1:5); through faith we inherit what has been promised (Heb 6:12); through faith Christ dwells in our hearts (Eph 3:17), through faith we hold eternal life (John 3:16). "...In his great mercy he has given us new birth into a living hope through the resurrection of Jesus Christ from the dead, and into an inheritance that can never perish, spoil or fade. This inheritance is kept in heaven for you, who through faith are shielded by God’s power until the coming of the salvation that is ready to be revealed in the last time....for you are receiving the end result of your faith, the salvation of your souls." -I Pet 1:3-9