Tafsir of Al-Fath 48:20

{Allah has promised you many spoils} These are the spoils that will accrue to the believers until the Day of Resurrection.

{And He hastened this for you} Meaning the spoils of Khaybar.

{And He restrained the hands of the people from you} Meaning the hands of the people of Khaybar and their allies from the tribes of Asad and Ghatafan when they came to support them. Allah cast terror into their hearts, so they retreated. It is also said: [This refers to] the hands of the people of Makkah through the peace treaty.

{And so that it may be} This restraint [of hands] is for the believers.

{And that He may guide you} And [provide] a lesson by which they know that they hold a [high] status with Allah Almighty, and that He is the guarantor of their victory and the conquest for them. It is said: The Messenger of Allah (peace be upon him) saw the conquest of Makkah in his dream, and the dreams of the Prophets (peace be upon them) are revelation. It was delayed until the following year, so He made the conquest of Khaybar a sign and a precursor for the conquest of Makkah.

{And guide you to a straight path} And increase you in insight, certainty, and trust in the bounty of Allah.

{And [He promises] others which you have not yet been able to take, but Allah has encompassed them. And Allah is over all things competent.}