Two words mentioned in the Qur'an are mukhlis (with I) and mukhlas (with A). They come from the same root word as "ikhlaas," which means sincerity.
The former is often translated as "a person of sincerity" or "sincere in actions," as in in Surah Ghafir:
So invoke Allah , [being] sincere to Him in religion, although the disbelievers dislike it.
In contrast, the latter is translated differently, such as the ayah in Surah As-Saffaat:
But not the chosen servants of Allah.
I remember in one khutbah, the speaker mentioned a very minute shade of difference between these two words, which are both similar in structure and meaning. What exactly is the meaning of both of these words, and what is the difference?