As Christians, we should act as Jesus did, with integrity, respecting and valuing others, "submitting to one another out of reverence for Christ...Showing proper respect to everyone” not treating them in a judgmental, self-centered or rude way (Eph 5:21; 1 Pet 2:17).
Our words and behaviour reveal our character and manners. The golden rule of treating people with dignity, is “Doing to them as you would they do to you” (Lk 6:31). Jesus said whatever we do (or don't do) to others is in fact doing it (or not doing it) to Him (Mt 25:40,45).
we are to be polite, showing respect to all people (1 Tim 5:1,2; Tit 3:2; 1 Pet 3:7).