Shaikh Dhul-Nun al-Misri (Allah have mercy on him) said,
‘There are three signs of humility:
1. Considering one’s self (nafs) to be the lowest of all the creatures. This is in order to find out its faults.
2. For the sanctity of Oneness of Allah (tawhid) respect and serve other people.
3. Accepting the truth and beneficial advice from any one (irrespective of his piety, faith, status, etc.)’
Awarif al-Ma’arif, page 415
Shara’iah, Makkah al-mukarramah