14-42
And do not think that Allah is unaware of that which the unjust do. He only gives them time till the day on which the eyes will stare (in horror),
The condition of the unjust on the day of resurrection is described.
14-46
And they had planned their plan, and their plan is with Allah, and if their plan was implemented (it would have been sufficient) for moving away mountains thereby.
The unjust had planned an evil plan which they could not implement. Allah (SWT) will punish them and keep up His promise to His messengers.
14-48
The day on which the earth will be changed to other than the (present) earth and the skies (too), and they will appear before Allah, the One, the Omnipotent.
There appears to be a hint in this verse about the theory of Oscillating Universe that the present expanding universe will collapse and rebound into a new universe 21:104 when the earth and the skies will be different from what they are now.
14-49
And on that day you will see the criminals linked together in chains,
The description of criminals in the hereafter is given.
14-52
This is a message for mankind that they may be warned thereby and that they may know that He is certainly one God, and that men of understanding may be mindful. (R 7)
The Quran is meant to warn against the punishment here and in the hereafter, to make mankind know that there is only one God and that is Allah (SWT) and to make the learned, who should take up the responsibility of propagating the Quran, mindful of this duty of theirs.