The Meaning of What Sincerity (Ikhlas) is
Muhammad Amin Ash-Shanquiti, when he was fourteen years old, he wrote one thousand verses of poetry, the genealogy of the tribes of the Arabian Peninsula.
But what was amazing is that when he became older, he actually took that one thousand verses of poetry and burned them and buried the ashes in the ground.
So all the scholars who used to read his stuff and were amazed by his intelligence and brilliance; when they heard about what he had done, they went and asked him why did he do that.
He answered:
“When I was fourteen years old, I didn’t understand what ikhlas was; and so at that point, I wanted to be better than all my friends and scholars who were studying to become great scholars.”
That is what ikhlas is; you sincerely make something purely for the sake of Allah.
What a beautiful place it would be! But because people don’t do things with the purest sincerity, our world these days is filled with the most atrocious of things; because the fact that people lack the most important ingredient in all of the actions, sincerity.
Ikhlas or sincerity is a word that is heavier than the universe and everything that it contains; it is the greatest action of the heart; it is the reason why Allah created me and you, it is that we may worship only one God.
They haven’t been commanded with anything except to worship Allah sincerely. (Quran 98:5)
Source: Discovering Islam