Was the statement of Aisha and Umar, may Allah be pleased with them, "Ask Ali," out of humility on their part, or was Ali, may Allah be pleased with him, more knowledgeable than them?

The status of Ali, may Allah be pleased with him, in knowledge and religion is clear, and it was known to Umar, Aisha, and other Companions. They did not refer to him in every issue, and sometimes, a referral does not imply his superiority. Aisha, may Allah be pleased with her, referred to Ali regarding wiping over the leather socks because he used to travel with the Prophet, peace and blessings be upon him. This indicates her awareness of his فضله (virtue/merit) and knowledge, and negates any personal dispute between them. As for Umar, may Allah be pleased with him, he used to prioritize Ali, consult him, and adopt his opinion in many matters, to the extent that it was said: Umar used to seek refuge from a difficult problem for which Abu Al-Hasan (Ali) was not available. This illustrates the Companions' eagerness for truth and their practice of giving people their rightful places.