Overall meaning : Allah has fulfilled His Messenger Muhammad’s true vision in which he saw that he had entered the Sacred Mosque secure and fearless. Therefore, you, Muhammad, and your companions will surely enter the Sacred Mosque next year, at the time He Himself wills, totally safe from the Quraysh’s harm and without fear at all, with some of you having their heads shaved while others having their hair shortened (as a rite for pilgrims).
Allah was fully aware of the benefits—which you did not know—behind His preventing you from entering Makkah in the year of Al-Hudaybiyyah, allowing you to enter it only the following year, so He first granted you, even before entering Makkah victoriously, a speedy victory, namely the truce of Al-Hudaybiyyah.
It is Allah who has sent forth His Messenger, Muhammad, with beneficial knowledge and the true religion—Islam—to make it prevail over all other religions. Sufficient is Allah as a witness.