Despite the fact that Lewis viewed pride as “the central issue in Christian morality” and it is a great sin in Narnia, the character of Reepicheep escapes condemnation because his pride is “a proper sense of dignity and worth” and his motives generous.
"The Honour and Glory of a Mouse: Reepicheep of Narnia,"
Mythlore: A Journal of J.R.R. Tolkien, C.S. Lewis, Charles Williams, and Mythopoeic Literature: Vol. 5
, Article 11.
Available at: https://dc.swosu.edu/mythlore/vol5/iss2/11