If a colleague was asked about something that you know, do not hasten to answer. Instead, you should only say something when you are asked. This is a better etiquette, and a nobler attituse. It generates interest in what you say, while enhancing your respect.
The honourable Tábi’í, Mujahid Ibn Jabr [Rahimahullah] recalled that Luqman, The Wise [Rahimahullah], said to his son, “If another person was asked a question, never hasten to give the answer, as if you are going to gain booty or win a prize.” By doing so, you will belittle the one who was asked, you will offend the questioner and you will draw the attention of the foolish people to your stupidity and ill-manner.
Shaykh Ibn Batta [Rahimahullah], the Hambalí jurist and Muhaddith said, “I was with Abu ‘Umar Az-Zahid Muhammad Ibn ‘Abdul Wahid Al-Baghdadi the Imam and linguist, also known as Ghulámu Tha’lab [Rahimahullah]. He (Abu ‘Umar [Rahimahullah]) was asked regarding an issue. I hastened and answered the enquirer. He turned to me and said, “Do you know the nosy and inquisitive ones?” suggesting that I was a nosy person. This made me feel very embarrassed.”