ترى الظالمين مشفقين مما كسبوا
You will see the wrongdoers fearful of that which they have earned,
means, in the arena of Resurrection.
وهو واقع بهم
and it will surely befall them.
means, the thing that they fear will undoubtedly happen to them. This is how they will be on the Day of Resurrection; they will be in a state of utter fear and terror.
والذين آمنوا وعملوا الصالحات في روضات الجنات
لهم ما يشاوون عند ربهم
But those who believe and do righteous deeds (will be) in the flowering meadows of the Gardens. They shall have whatsoever they desire with their Lord.
What comparison can there be between the former and the latter How can the one who will be in the arena of resurrection in a state of humiliation and fear, deserving it for his wrongdoing, be compared with the one who will be in the gardens of Paradise, enjoying whatever he wants of food, drink, clothing, dwellings, scenery, spouses and other delights such as no eye has seen, no ear has heard, and has never crossed the minds of men.
Allah says:
ذلك هو الفضل الكبير
That is the supreme grace.
means, the ultimate victory and complete blessing