with constancy

See: faithfully
References in classic literature ?
They went on in their own wild way for a little while--I never stopped them; I enjoyed it too much myself-- and then we gradually fell to considering how young they were, and how there must be a lapse of several years before this early love could come to anything, and how it could come to happiness only if it were real and lasting and inspired them with a steady resolution to do their duty to each other, with constancy, fortitude, and perseverance, each always for the other's sake.
Key statement: The degree of tire wear is estimated with constancy and accuracy even when the road surface becomes rough during a vehicular run.
I would ask from my season here to be a regular and to have the possibility of training with constancy without any problems.