Answer: It is the quality of not thinking that one is better than other people; thus, one does not despise people or reject the truth.

Allah Almighty says: {The slaves of the Most Compassionate are those who walk on earth humbly.} [Surat al-Furqān: 63] It means that they are humble. Moreover, the Prophet (may Allah's peace and blessings be upon him) said: "No one humbles himself seeking the pleasure of Allah except that Allah will raise his rank." [Narrated by Muslim] The Prophet (may Allah's peace and blessings be upon him) also said: "Allah revealed to me that you should all be humble; so that people should not feel proud over one another, and that they should not wrong one another." [Narrated by Muslim]