God the Father, God the Son, God the Holy Spirit = Trinity

1 Peter 1:

2
Peter laid the theological foundations for this letter of encouragement. “God” the Father in His grace had chosen them and God the “Spirit” had sanctified them through the atoning blood of God the Son, Jesus Christ. (All three Persons of the Trinity are mentioned in this verse.) Thus Peter greeted his readers with the prayerful wish that they might experience in abundance God’s grace (charis) and peace!