Surah Al-Munafiqoon warns the believers to not neglect Allah due to the blessings of this world and urges them to spend in the way of Allah.
Abu Abdillah ... said: "Khums of Allah is for the Imam, Khums of the Prophet is for the Imam, Khums of relatives is for the relatives of the Prophet, i.e. the Imam; and the orphans are the orphans of the family of the Prophet, and the needy are the needy from them, and the travellers are the travellers from them; and nobody else can take their place."
Fadak is the name of a piece of farming land around Medina that came under the ownership of the Holy Prophet after the peace treaty with the Jews of that area.
... that the one who established the Hijri Calendar was the Prophet himself