A man came to the Prophet and said: O Messenger of Allah! Who from amongst mankind warrants the best companionship from me? He replied: "Your mother." The man asked: Then who? So he replied: "Your mother." The man then asked: Then who? So the Prophet replied again: "Your mother." The man then asked: Then who? So he replied: "Then your father." (Sahîh Bukhârî 5971 and Sahîh Muslim 7/2)

Commenting on this hadith, Shaykh Muhammad Ali Al-Hashimi notes:

This hadith confirms that the Prophet (peace and blessings be upon him) gave precedence to kind treatment of one's mother over kind treatment of one's father (Al-Hashimi, The Ideal Muslimah, IIPH 2005, p. 165)