“So, one is “good” so long as Jesus is in them; otherwise, they are bad?” So then, only Christians are good?

Christian response,

The “goodness” or righteousness of Jesus is gifted-imputed by New Covenant promise over the life of the one who believes that Jesus is Messiah (2 Corinthians 5:21; Hebrews 8:12). Man is sinful by nature (Romans 5:12) and can therefore NEVER attain self-righteousness sufficient to please the Father (Ephesians 2:8-9; Romans 4:1-8), but the Father has made a way for mankind to receive divine righteousness that is gifted-imputed-promised through faith in Jesus (2 Corinthians 5:21).

What did Jesus do for you and me in the New Covenant?

Jesus took our sin upon Himself and paid the required price for that sin which is “blood atonement” as per Leviticus 17:11 (1 Peter 1:18-19; Genesis 3:21); the animal blood sacrifices performed in the Old Covenant foreshadowed the blood sacrifice of Messiah Jesus upon a Roman Cross (Matthew 26:28) yet the blood of animals could never take away sin (Hebrews 10:4); only the precious blood of Jesus makes acceptable atonement for sin (1 Peter 1:18-19). In the Old Covenant blood sacrifices, it was NOT the blood of the animal that resulted in righteousness (a right standing) with the Father but it was the “faith” of the one offering the sacrifice that engendered Covenant-righteousness (Hebrews 11); faith being a “sincere trust” that Elohim would do exactly as He has promised. It is the sinless blood of Jesus that provides a divine Path to life in Eternity (John 14:6; John 3:16; Matthew 26:28).

Righteousness in the New Covenant,

In the New Covenant, as established in the blood of Jesus (Matthew 26:28), the Father agrees to forgive and forget the sins of the one who trusts in Jesus as their payment (propitiation) for sin (Hebrews 8:12) and the Father then endows the one forgiven of sin with the indwelling Holy Spirit (Ephesians 1:13-14; John 14:16; Ezekiel 36:27) and it is the indwelling Holy Spirit who begins a new work or a work of righteousness in the “new man” (2 Corinthians 5:17) and daily, the Holy Spirit begins to produce divine “fruit” through the faithful in Jesus (Galatians 5:16-23). It is this divine “fruit” that fulfills all Law and that same “fruit” honors the Father (John 15:8) as the Spirit incrementally transforms the redeemed into the obedient image of Jesus; this divine transformation is a life-long pursuit as the Spirit prepares the redeemed for service in the coming New Jerusalem where those who have loved and trusted in Jesus will serve Him in resurrected bodes, eternally (Philippians 3:21; Revelation 21-22).

“Goodness” concerning humanity?

There is nothing intrinsically “good” in humanity (Romans 3:23; Romans 5:12); this, due the Adamic sin-nature but godly “goodness” comes through faith in Jesus and that goodness is gifted by Covenant promise (Hebrews 8:12); the Christian is a sinner by nature (Romans 5:12) and is redeemed by faith in Jesus and consequently they become a New Creation (2 Corinthians 5:17) and though they are not “perfect” in reality, they are NOT what they used to be as servants of Satan and they are now walking in the path of studious obedience (Philippians 2:12; 2 Timothy 2:15) seeking to honor the Father and Jesus and the Spirit who has provided them a new life and eternal Hope (Galatians 5:16).

Christians are NOT perfect, yet…

Christians still struggle with the sin-nature that is integral with the flesh (Romans 5:12; Romans 7:14-25) but the Christian, unlike the lost in Satan, are divinely anointed and empowered and guaranteed life by the indwelling Holy Spirit and consequently have peace with the Father (Romans 5:1) and the Christian walks in victory as Jesus is victorious over the Devil and the Devil’s works which are Death-Hell-the Grave (Revelation 5:5). Christians become divinely perfect the moment they shed this body of fleshly, decaying, death and enter into the presence of our Lord and Savior, Jesus Christ (2 Corinthians 5:8).