Misunderstanding: "The word 'Trinity' does not appear in the Bible; it is a belief made up by Christians in the 4th century."
Truth: It is true that the word "Trinity" does not appear in the bible but the Trinity is nevertheless a Bible-based belief. the word "Bible" does not appear in the Bible either.
The word "Trinity: was used to explain the eternal relationship between the Father, the Son, and the Holy Spirit. Many Bible passages express the Trinity. False beliefs flourished during the early days of Christianity, and still do. Early Christians constantly defended their beliefs. The following early church leaders and/or writings all defended the doctrine of the Trinity long before A.D. 300.
Approximate Dates:
A.D. 96 Clement, the third bishop of Rome
A.D. 90-100 The Teachings of the Twelve Apostles, the "Didache"
A.D. 90? Ignathius, bishop of Antioch
A.D. 155 Justin Martyr, great Christian writer
A.D. 168 Theophilus, the sixth bishop of Antioch
A.D. 177 Athenagoras, theologian
A.D. 180 Irenaeus, bishop of Lyons
A.D. 197 Tertullian, early church leader
A.D. 264 Gregory Thaumaturgus, early church leader