Show me the Scripture that says that "All Christian terminology must come directly from the Bible."
If it is not in the Bible then it is man's teachings and not God's.
Luke 1:1-4 Many have undertaken to draw up an account of the things that have been fulfilled among us, just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. Therefore,
since I myself have carefully investigated everything from the beginning, it seemed good also to me to write an orderly account for you, most excellent Theophilus,
so that you may know the certainty of the things you have been taught.
The NEW TESTAMENT is fulfillment of the OLD TESTAMENT.
The Old Testament were prophecies about what was coming.
We have God's prophecies made known to us in the New Testament.
Romans 16:25-27 Now to him who is able to establish you by my gospel and the proclamation of Jesus Christ,
according to the revelation of the mystery hidden for long ages past, but now revealed and made known through the prophetic writings by the command of the eternal God, so that all nations might believe and obey him–to the only wise God be glory forever through Jesus Christ! Amen.
2 Peter 1:19 We also have
the prophetic message as something completely reliable, and you will do well to pay attention to it, as to a light shining in a dark place, until the day dawns and the morning star rises in your hearts.
The Old Testament is the prophetic message.
The New Testament is the prophetic message revealed.
We do not make up things and then say where does the scriptures say we cannot do that. That would be adding to God's Word.