Many of us talk much and listen little. Of the manners in Islam is the art of listening when a person starts to tell you something whether in private or in the company of others. If what that person is talking about is something you already know very well, you should not hasten to let everyone know, but you should pretend as if you do not know it. One major issue amongst Muslims today is that we rush in to reveal our knowledge or to interfere in speech, not considering the person who is speaking or the severity of illness in our ettiquettes. One should show attention and concentration no matter what.
One of the Tabi'i Imam Ata ibn Abi Rabah (رضى الله عنه) said:
"A young man would tell me something that I may have heard before he was borm. Nevertheless, I listen to him as if I had never heard it before."
Khalid ibn Safwan al-Tamimi, who frequented the courts of the two Khalif'as Umar ibn And' al-Aziz (رضى الله عنه) and Hisham ibn 'Abd al-Malik (رضى الله عنه) said:
"If a person tells you something you have heard before, or news that you already learnt, do not interrupt him to exhibit your knowledge to those present. This is rude and ill mannered."
" Learn the art of listening as you learn the art of speaking"
Listening well means to maintain eye contact (when appropriate), allowing the speaker to finish their speech and restraining your urge to interrupt his speech.
"Never interrupt a talk, though you know it inside out".
- Al Hafiz al-Khatib al-Baghdadi
So one must try to be an attentive listener, giving the speaker respect while they talk, not harming them physically or mentally. We should think before we speak. Whether we agree or disagree with what is being said, we should always follow the correct ettiquette as Muslims.
(-Taken from a blog on Mufti Mohammed bin Adam's commentary on Shaykh Abdul Fattah Abu Ghudda's 'min Adab il Islam')