Mr Knightley had seemed to dislike Frank Churchill from very early on -- in the earlier chapters when he wrote excuses delaying his visit to his father and Mrs Weston -- "his letters disgust me". said Mr Knightley when everybody else said what fine letters Frank wrote.

Did Mr Knightley's early dislike prejudice him agaisnt Frank, making him suspicious of Frank's dealings with young ladies such as Emma and Jane?

But it could be the other way round, i.e. that Mr Knightley could not get over his early dislike because he became jealous of the young, handsome Frank Churchill. Before Frank Churchill, the only handsome young gentleman around was apparently Mr Elton.