One God, Three Persons (Matthew 3:13-17) The sermon expounds on the doctrine of the Trinity, asserting that one God exists eternally in three distinct persons: Father, Son, and Holy Spirit. Using Matthew 3 as the primary text, it illustrates this mystery through Jesus' baptism, where all three persons are simultaneously present and active. The preacher emphasizes that mere intellectual belief in God is insufficient for salvation, contrasting true faith with the trembling belief of demons. Central to the message is the gospel truth that Christ identifies with sinners to fulfill righteousness and bear their judgment on the cross. Ultimately, the sermon calls listeners to personal repentance and faith, urging them to rely on the triune God's grace rather than their own religious efforts.