إِنَّ السَّاعَةَ ءاَتِيَةٌ
...
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,
...
أَكَادُ أُخْفِيهَا
...
I 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,
أَكَادُ أُخْفِيهَا
(I am almost hiding it),
"This means that no one knows its appointed time except Me (Allah)."
Allah also said,
ثَقُلَتْ فِى السَّمَـوَتِ وَالاٌّرْضِ لاَ تَأْتِيكُمْ إِلاَّ بَغْتَةً
Heavy is its burden through the heavens and the earth. It shall not come upon you except all of a sudden. (7:187)
This means that its knowledge weighs heavily upon the dwellers of the heavens and the earth.
Concerning Allah's statement,
...
لِتُجْزَى كُلُّ نَفْسٍ بِمَا تَسْعَى
that every person may be rewarded for that which he strives.
"I will establish it and it is inevitable. I will certainly reward every person who does something, according to what he did."
فَمَن يَعْمَلْ مِثْقَالَ ذَرَّةٍ خَيْراً يَرَهُ
وَمَن يَعْـمَلْ مِثْقَالَ ذَرَّةٍ شَرّاً يَرَهُ
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. (99:7-8)
إِنَّمَا تُجْزَوْنَ مَا كُنتُمْ تَعْمَلُونَ
You are only being requited for what you used to do. (52:16)
Allah said,