Look at the word Christian another way, just take away the "a" and you have - Christ-In.
"...if you confess with your mouth, 'Jesus is Lord,' and believe in your heart that God raised him from the dead, you will be saved." (Romans 10:9) - THEN you are a Christian. Christ comes in to your life.
Believers in Christ have done nothing but have Faith in His Grace. Christ paid it All. The incredible thing is to realize and stand on all the additional benefits Christians receive by being In Christ.The realization that we have a powerful relationship with the God of Creation, our Salvation, and our future should lead us to the question - now that God is in us what do we find In Him? This is what my research found (not exhaustive).
The Christian's righteousness or right-standing with God comes In Christ. Romans 3:22 The Christian has become alive! We were dead in our sins, now because of Christ we are alive! Romans 6:11 The Christian is granted eternal life, not eternal death/suffering, In Christ. Romans 6:23
There can be nothing of a condemning nature brought upon Christians that Christ has not taken care of on The Cross and who truly follow Him. Romans 8:1 In Christ, God's love is never, ever going to leave the Christian. Romans 8:39 In Christ, the truth resides by the power of the Holy Spirit and comes out verbally with the Holy Spirit testifying to His Word. Romans 9:1
In Christ, Christians are one. Romans 12:5 In Christ, Christians glory or boast in their Lord as they serve God. Romans 15:17 Christians work, In Christ. Romans 16:3 Christians are tested and approved, In Christ Romans 15:10 Christians are called out and set aside for God's purpose(s), In Christ. 1 Corinthians 1:2 Christians are graced by God, In Christ. 1 Corinthians 1:4 In Christ, we start off as "mere infants". 1 Corinthians 3:1 With the years and circumstances of life comes maturity - In Christ. 1 Corinthians 4:10 Christians have many helpful eyes and hands throughout our lives and only one leader of the local church you are attending. 1 Corinthians 4:15
For the Christian, there is a way of life In Christ. 1 Corinthians 4:17 For the Christian, God's promises are "Yes" because we are In Christ. 2 Corinthians 1:20 In Christ, the Christian can be bold, confident, and courageous. 2 Cor. 1:21 The Christian is shown off by Christ as we "spread everywhere the fragrance of the knowledge of him". 2 Cor. 2:14 Christians are new people with a new lifestyle because of Christ 2 Cor. 5:17
Christians are Fishers of Men (Matt. 4:19), Salt of the Earth (Matt. 5:13), Light of the World (Matt. 5:14), Helpers of the Needy (Matt. 6:1-4), Prayerful People (Matt. 6:5-13), Forgiving People (Matt. 6:14-15), Fasting People (Matt. 6:16-18), Instruments of Healing (Matt. 10:8), Binders and Loosers (Matt. 16:19), Brothers, Sisters, and Mothers (Matt. 12:48-50)...In Christ.
The transformation one accepts is major. It is all because of Christ Jesus. In Christ Jesus I live and move and have my being (Acts 17:28). He is the sustainer of my life. I can do nothing of eternal value without Him. Life and life more abundantly is all because of inviting Christ-In and then finding and standing on what we have In-Christ!