Allah, the Exalted, says,

This is referring to the fire when he approached it.

In another Ayah it says,

He was called from the right side of the valley, in the blessed place, from the tree: "O Musa! Verily, I am Allah."
However, here Allah says,

meaning, ‘the One Who is talking to you and addressing you,’

‘Ali bin Abi Talib, Abu Dharr, Abu Ayyub and others of the Salaf said, “They (his sandals) were from the skin of a donkey that was not slaughtered.” It has also been said that he was only commanded to remove his sandals due to respect for the blessed spot.

Concerning Allah’s statement,

{Tinva} ‘Ali bin Abi Talhah said that Ibn ‘Abbas said, “It is the name of the valley.” Others have said the same. This is merely mentioned as something to give more explanation to the story. It has also been said that it is a figure of speech, which comes from the command to place his feet down. It has also been said that it means ‘doubly sacred’ and that Tuwa is something that has repetitious blessings. However, the first opinion is most correct. It is similar to Allah’s statement,

When his Lord called him in the sacred valley of Tuwa.

Allah’s statement,

{And I have chosen you.'} is similar to His statement,

1 have chosen you above men by My Messages, and by My speaking (to you).

This means over all human beings of that time. It has also been said that Allah said, “O Musa, do you know why I chose to speak to you directly out of all of the people?” Musa said, “No.” Allah then said, “Because 1 have not made anyone humble himself as much as you have humbled yourself.”
Concerning Allah’s statement,

“Now listen to what I say to you and what I reveal to you.”

This is the first obligation upon all responsible people of age, that they know that there is no God worthy of worship except Allah alone, Who has no partners.
Concerning Allah’s statement,

{so worship Me,} This means, “Single Me out alone for worship, and establish My worship without associating anything with Me.”

It has been said that this means, “Pray in order to remember Me.” It has also been said that it means, “And establish the prayer whenever you remember Me.” There is a supporting evidence for this second statement in a Hadith recorded by Imam Ahmad from Anas, who said that the Messenger of Allah said,

«Whenever one of you sleeps past the prayer, or he forgets to pray, then let him pray when he remembers it. For verily, Allah said, {And perform Salah for My remembrance.}»

In the Two Sahihs it is reported from Anas that the Messenger of Allah said,

«Whoever slept past tire prayer, or forgot it, then his expiation is that he prays it when he remembers it. Tlrere is no expiation for it other than f/i«f.»
Concerning Allah’s statement,

{Verily, the Hour is coming} This means that it is established and there is no avoiding it. It will be and it is inevitable.
Concerning Allah’s statement,

{1 am almost hiding it} Ad-Dahhak related from Ibn ‘Abbas that he used to recite it as, “I almost kept it hidden - from myself.” Ibn ‘Abbas then would say, “Because nothing is ever hidden from Allah’s Self.” ‘Ali bin Abi Talhah reported from Ibn ‘Abbas that he said,

{1 am almost hiding it} “This means that no one knows its appointed time except Me (Allah)."
Allah also said,

Heavy is its burden through the heavens and the earth. It shall not come upon you except all of a sudden.

This means that its knowledge weighs heavily upon the dwellers of the heavens and the earth.

Concerning Allah’s statement,

I will establish it and it is inevitable. I will certainly reward every person who does something, according to what he did.”

So whosoever does good equal to the weight of an atom shall see it. And whosoever does evil equal to the weight of an atom shall see it.

You are only being requited for what you used to do.
Allah said,

The address here is directed towards all individuals who are responsible (and capable of taking heed to this message). This means, “Do not follow the way of the person who does not believe in the Hour (Day of Judgement) and he only pursues his desires in this worldly life. He disobeys his Lord and only follows his desires. Whoever behaves like these people, then verily he has failed and lost.

{lest you perish.} This means that you will be destroyed and ruined.

And what will his wealth avail him when he goes down (in destruction)?