It is narrated on the authority of
`Ikrimah that the meaning of Salah and slaughtering in Allah's saying:
Verily, We have granted you (O Muhammad صلى الله عليه وسلم) Al-Kauthar (a river in Paradise).
Therefore turn in prayer to your Lord and sacrifice (to Him only).
This means Salat-ul-`Eid and slaughtering of the Ud-hiyah.
The correct meaning
is: Allah commanded His Messenger Muhammad (peace be upon him) to make his Salah -whether obligatory or supererogatory- and his slaughtering, purely for Allah Alone who has no partner with Him as in His saying to his Messenger (peace be upon him):
Say (O Muhammad صلى الله عليه وسلم): "Verily, my Salât (prayer), my sacrifice, my living, and my dying are for Allâh, the Lord of the ‘Alamîn (mankind, jinn and all that exists).
"He has no partner. And of this I have been commanded, and I am the first of the Muslims."
As for the Sunnah regarding offering the Ud-hiyah, it is authentically reported from the sayings and actions of the Prophet (peace be upon him). Every ruling does not necessarily have to be detailed in the Qur'an, as it is enough for it to be proven by the Prophet (peace be upon him) because of Allah's (Exalted be He) saying:
And whatsoever the Messenger (Muhammad صلى الله عليه وسلم) gives you, take it; and whatsoever he forbids you, abstain (from it).
(Part No. 11; Page No. 393) And His Saying:
And We have also sent down unto you (O Muhammad صلى الله عليه و سلم) the Dhikr [reminder and the advice (i.e. the Qur’ân)], that you may explain clearly to men what is sent down to them
and His saying:
He who obeys the Messenger (Muhammad صلى الله عليه وسلم), has indeed obeyed Allâh
along with other Ayahs that have the same meaning.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.