What is the ruling on glorifying a person and equating him with God? And how can one avoid polytheism (shirk)?

Exalting a person and equating him with Allah in love, reverence, and worship is major shirk (definition) (polytheism), because it sets up a rival to Allah.

Worship has two pillars: love and reverence. Through love comes hope and the performance of commands, and through reverence, one abandons prohibitions out of fear of Allah's punishment.

To avoid shirk: - Block the means that lead to it, such as prohibiting prayer at graves. - Avoid polytheistic expressions, such as swearing by other than Allah. - Abandon anything that leads to attachment to persons, images, and relics. - Be moderate in loving and praising people, as the Prophet, peace and blessings be upon him, said: "Do not exaggerate in praising me as the Christians exaggerated in praising the son of Mary." - Learn the correct creed and what contradicts it from innovations and deviations. - Supplicate to Allah to keep one away from shirk, just as Ibrahim, peace be upon him, used to supplicate: "And keep me and my sons away from worshipping idols." - Supplicate: "O Allah, we seek refuge in You from knowingly associating anything with You, and we seek Your forgiveness for what we do not know."