Historically, heresies have seldom involved disputes over what the Bible does say, but rather interpretations of what it doesn't say.
At the time of Constantine and the Council of Nicaea, heresies were declared over words like "homoousios", and "hypostasis", neither of which are found in the Bible.
The word “Pope” isn’t found in the Bible either.
Homoousios is a word that tells us that when Jesus said, “The Father and I are one.” he meant exactly that. Arius would not use the term because he interpreted the term to be a figure of speech. He and his followers did not think that Jesus was God Incarnate.