Salvation is when God called you out of darkness into the light. When you see the light, it comes quickly to dispel darkness. The change is sudden and abrupt. Darkness is defeated immediately in the presence of light. That's the way God's grace changes people who have lived in darkness. Salvation is from "Him who called you out of darkness into His marvelous light" (1 Peter 2:9).
Darkness is used as a metaphorical expression for those who cannot see the truth in Christ our Lord. It is spiritual blindness. When the Holy Spirit calls us effectively to Christ, the eyes of our understanding are opened. We see the light of truth in Christ. Then we can testify, "I once was blind but now I see."
God called you to the light of our Lord Jesus Christ. He said, "I am the light of the world. He who follows me shall not walk in darkness, but have the light of life" (John 8:12). When you see the light, you see the glory of God in Jesus Christ. He is the light of life. Salvation is from darkness into the light.
God called you to the light that always overcomes the darkness. It is not your achievement. Rather, the light comes to you from without, changing your heart within. Light is God's Spirit working in your dark heart. Then, your testimony is in these words, "I saw the light." Give all the glory to "Him who called you out of darkness into His marvelous light."