What is the meaning of sincerity in one's deeds for the sake of Allah?

Question:
May Allah reward you with good. This questioner says: Honorable Shaykh, what is the meaning of sincerity? And if a servant intends something other than Allah with his worship, what is the ruling?

Answer:
Sincerity means that there is no intention for anyone other than Allah in it, and that it contains no major or minor shirk (associating partners with Allah). Rather, it must be pure for the face of Allah (Mighty and Majestic). If one intends showing off or seeking fame along with it, it becomes invalid. Or if one intends shirk with Allah (Mighty and Majestic) along with it, it becomes invalid, because shirk invalidates the deed. If it is major shirk, it invalidates all deeds. If it is minor shirk, such as showing off or seeking fame, it invalidates the specific deed that was mixed with it. So the Muslim must make his deeds pure for Allah (Mighty and Majestic), free from major shirk, minor shirk, and all other intentions. However, if he intends, along with his intention for Allah, a permissible matter that benefits him, this is not considered shirk; it is considered seeking help through what Allah (Mighty and Majestic) has made lawful.
Such as one who maintains family ties intending to draw near to Allah through that, and intending to lengthen his lifespan or his life, as in the hadith because this is a permissible matter. Yes.