Abu Yazid on Humility: He is not humble until he lowers his ego

Al-Ghazali reported: Abu Yazid, may Allah have mercy on him, said, “As long as a servant thinks there is someone in the creation more evil than himself, he is arrogant.” It was said, “When will he be humble?” Abu Yazid said, “When he views himself as having no special station or status. The humility of every human being is by the measure of his knowledge of his Lord Almighty and knowledge of himself.”

Source: Iḥyā’ Ulūm al-Dīn 3/343

عن الغزالي قال أبو يزيد رحمه الله ما دام العبد يظن أن في الخلق من هو شر منه فهو متكبر فقيل له فمتى يكون متواضعاً قال إذا لم ير لنفسه مقاماً ولا حالاً وتواضع كل إنسان على قدر معرفته بربه عز وجل ومعرفته بنفسه

3/343 إحياء علوم الدين