In Islam, superiority is given to those who are better in terms of piousness and beneficial knowledge. Almighty Allah says, “Verily the most honoured of you in the sight of Allah is (he who is) the most righteous of you.” (Al-Hujurat, 49:13) Also, Almighty Allah says, “…Say (unto them, O Muhammad): Are those who know equal with those who know not? But only men of understanding will pay heed…” (Az-Zumar: 9) Therefore, we have to show respect to every knowledgeable person, due to the knowledge he or she has.
As regards parents, we are also ordered to be dutiful to them, obey their orders and be merciful with them. Being dutiful to parents is among the greatest commands of Islam and a wide way to enter paradise. There are many hadiths to this effect.