Amir al-Momineen Sayyidina Ali ibn e Abi Taleb (Allah be pleased with him) said,
1. Absolutely do not keep expectations from anyone except Allah.
2. Do not be afraid of anything except your own sins.
3. Do not be ashamed to learn something you do not know.
4. If you do not know the answer of a question acknowledge your ignorance openly.
Al-Murtaza, by Sayyid Abul Hasan Ali Nadwi (Allah ahve mercy on Him), page 290