The most common and most likely answer to this crossword clue is the 8 letter word LUTHERAN
I've seen this crossword clue in The Times
L
U
T
H
E
R
A
N
More clues leading to the result LUTHERAN
- In airport goddess replaces old Christian
- Christian left university and rushed to pen article
- Protestant with stringed instrument managed to capture hearts
- Say Bach’s instrument managed to capture hearts
- Initially lazy, neutral converts Protestant
- Speared by Zulu, the rancorous Protestant
- Maybe Bach read French at the Royal Academy of Arts? Not initially
- University student returned article published about Protestant movement
Buddy explains!

The straight part
We know that "Christian" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case christian = lutheran.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.