Kant preferred to treat respect for others as a kind of duty. He seems to have had severe doubts about empathy or sympathy as a kind of feeling, on the ground that all such feeling involves our empirical inclinations, rather than pure moral concern.
Feeling is a mixed form that involves both emotional and rational elements. Although he did recognize the important ethical role of something like character formation — which would seem to necessarily involve a significant emotional component — Kant’s treatment of emotion often seems closer to the Stoic position that all “passion” must be something bad, than it does to the Aristotelian alternative that we should seek a healthy interweaving of reason and emotion.
I want to take a more optimistic, Aristotelian view of the place of emotion in a life of reason. Kant makes a valid point that inclination in general may lead us to deceive ourselves, but I think he went too far in distrusting anything toward which we feel inclined. We may be inclined to do what could independently be assessed as the right thing, and in such cases I think the inclination ought to be welcomed. (See also Kant’s Groundwork; Aristotle and Kant; Ethos, Hexis; Practical Judgment.)