Pride is as great a sin as polytheism
Pride, with its consequences, remains a great sin opposing the purpose for which Allaah (subhaanahu wa ta’aala) created His creation, just as the greatest sin, polytheism. Allaah (subhaanahu wa ta’aala) created His creation and revealed His Book in order that complete obedience be devoted to Him, Alone. Therefore, He (subhaanahu wa ta’aala) forbade the entry into Paradise for polytheists and any of those who have the weight of a mustard seed of pride in their hearts.
Spiritual Disease and its Cure, Ibn Qayyim
taken from: http://daragharbi.org