The disbelievers were staunch in their transgression of ascribing deities to Allah swt and in complete denial of the message that the prophet saw brought, mocking and ridiculing the belief of worshipping Allah swt alone and the coming of the Day of Reckoning.
In Surah Sad, we learn how many of the prophets were tried and tested. When the prophets realised their mistakes, they immediately turned to Allah swt in seeking forgiveness, and their status became even more elevated in the eyes of Allah swt. The surah ends with the Prophet saw persisting in advising the disbelievers, in an attempt to see the error of their ways before it is too late for them.
