In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Beware of the disease of the despots: [pride] (a); for indeed pride, avarice and [blameworthy] envy were the first [sins] Allaah was disobeyed with.(b) So raising yourself above your teacher is pride(c); and being arrogant towards the one who benefits you from amongst those who are below you [in knowledge] is pride; (d) and your falling short in acting upon knowledge is a sludge of pride and an indication of being deprived of [well-being].(c)
[a] The Prophet said: Pride is to reject the truth and mock at the people. [b] This refers to shaytaan’s behaviour when he was commanded to prostrate to Aadam, but pride prevented him from doing so. He refused and was haughty. [c] Raising oneself can either be by way of the tongue [i.e. speech] and it can also be by way of sentiments [feelings, attitude, behaviour etc]. He [i.e. the student] might be walking with his teacher, whilst swaggering and saying: I did this and I did this. [d] Likewise, being arrogant towards the one who is below you in knowledge is pride. This also occurs from some of the students. If someone below him in knowledge informs him of something, you find him arrogant and does not accept. [e] We ask Allaah for wellbeing because from the types of pride is to not act upon the knowledge one knows. [Source: An Excerpt from ‘Sharh Hilyati Taalibil Ilm’ pages 38-40′ by Shaikh Uthaymeen (rahimahullaah). slightly paraphrased]