This refers to how Allah sends revelation. Sometimes He casts something into the heart of the Prophet, and he has no doubt that it is from Allah, as it was reported in Sahih Ibn Hibban that the Messenger of Allah said:

«Ar-Ruh Al-Qudus (i.e., Jibril) breathed into my heart that no soul will die until its allotted provision and time have expired, so have Taqwa of Allah and keep seeking in a good (and lawful) way.»

{or from behind a veil} - as He spoke to Musa, peace be upon him. He asked to see Him after He had spoken to him, but this was not granted to him.

In the Sahih, it recorded that the Messenger of Allah said to Jabir bin 'Abdullah, may Allah be pleased with him:

«Allah never speaks to anyone except from behind a veil, but He spoke to your father directly.»

This is how it was stated in the Hadith. He (Jabir's father) was killed on the day of Uhud, but this refers to the realm of Al-Barzakh, whereas the Ayah speaks of this earthly realm.

as Jibril, peace be upon him, and other angels came down to the Prophets, peace be upon them.

{Verily, He is Most High, Most Wise.} He is Most High, All-Knowing, Most Wise.

means, the Qur'an.

means, 'in the details which were given to you in the Qur'an.'

{But We have made it} means, the Qur'an,

This is like the Ayah:

{And verily, you} means, 'O Muhammad,'

{are indeed guiding to a straight path.} means, the correct behavior. Then Allah explains this further by saying:

{The path of Allah} meaning, His Laws which He enjoins.

means, their Lord and Sovereign, the One Who is controlling and ruling them, Whose decree cannot be overturned.

{Verily, all matters at the end go to Allah.} means, all matters come back to Him and He issues judgement concerning them. Glorified and exalted be He far above all that the evildoers and deniers say.

[This is the end of the Tafsir of Surat Ash-Shura]