If I'm reading the Athanasian Creed correctly, it says a belief in the Trinity is necessary for salvation. Could you please elaborate on this a little bit? How could a person be lost if they don't believe in the Trinity, which is a difficult concept for people to comprehend. I believe in the Trinity, but I've always found the Athanasian Creed a bit troubling because I do not fully understand how a belief in the Trinity relates to the Gospel. Maybe it is simply because the Athanasian Creed was written to combat heresies that said Jesus was only a man?
You are reading and understanding the Athanasian Creed correctly. The Bible teaches that there is salvation only through faith in Jesus Christ, the Son of God (John 14:6; Acts 4:12).
As you suggested, the Athanasian Creed was written to combat heresies that Jesus is inferior to God the Father. If Jesus is not God, then God is not triune; a denial of Jesus is a denial of the Father (John 5:22-23).
The doctrine of the Trinity certainly “is a difficult concept for people to comprehend.” Thankfully, saving faith does not mean that people need to understand all the complexities of biblical doctrines. Saving faith is trust, acceptance and reliance on what God declares about himself and his works (Hebrews 11:1). Saving faith is trust in the God the Bible, who reveals himself in Scripture as a triune God.
The Athanasian Creed does not condemn Christians who struggle to understand a God who is far superior to them in every way. The Athanasian Creed does condemn those who deny the deity of Christ and the doctrine of the Trinity.