Translation of the verse 7 from Surah Al-Mursalat : Number of verses 50 - - page 580 - Part 29.
Surely, what you are promised must come to pass.
Indeed, what you are promised is to occur.
(77:7) Surely what you are promised *2 shall come to pass. *3
*2) Another meaning can be; "That which you are being threatened with," i. e. the Resurrection and Hereafter.
*3) Here an oath has been sworn by five things on the inevitability of the Resurrection:
(1) "Those which are sent forth in succession, or for a good cause;"
(2) "those which blow violently and tempestuously
(3) "those which disperse and scatter;"
(4) "those which split and separate;" and
(5) "those which inspire the remembrance." As these words only describe the characteristics and it has not been specified what thing or things they qualify, this has given rise to a difference of opinion among the commentators as to whether these are the qualities of one particular thing or of different things and what the thing or things are. One group of them says that all the five qualify the winds; the second group says that all the five imply the angels; the third group says that the first three imply the winds and the remaining two the angels; the fourth says that the first two imply the winds and the other three the angels; another group has opined that the first quality implies the angels of mercy, the second the angels of punishment and the remaining three imply the verses of the Qur'an.
In our opinion, the first thing worthy of consideration is that when five characteristic have been mentioned continuously in one and the same context and there is no indication to show as to what has been qualified up to a certain point and wherefrom has the qualification of another thing begun, it cannot be correct, on the basis of a baseless conjecture, to understand that in these verses oaths have been sworn by two or three different things. Rather in this case the continuity of the subject by itself requires that the whole passage be regarded as related to the characteristics of one and the same thing. Secondly, wherever in the Qur'an an oath bas been sworn by a certain thing or, things in order to convince the doubters or deniers of an unseen truth, there the oath stands for an argument or reasoning which is meant to tell that the thing or things point to the truth's being right and correct. For this purpose obviously it cannot be correct to present one imperceptible thing as an argument for another imperceptible thing; for, only a perceptible thing can be presented as an argument for an imperceptible thing. Hence in our opinion the correct explanation is that it implies the winds and the explanation of the people who interpret the five things to mean the angels cannot; be acceptable, for the angels are as imperceptible as is the occurrence of the Resurrection.
Now, let us consider as to how these different states of winds point to the occurrence of the Resurrection. One of the most important factor which has made animal and vegetable life possible on the earth is the air. The relationship its qualities bear with every kind of life testify that there is an all-powerful, All-Wise Creator, Who willed to create life on this earth and for this purpose created here a thing whose qualities exactly and precisely correspond to the requirements of the existence of living beings. Then, He did not only wrap up the earth in the air and left it alone, but by His power and wisdom characterised this air with countless different states, which are being regulated since millions and millions of years in such a way that they cause the change of seasons and weather sometimes it is close and sometimes a soft breeze blows sometimes it is hot and sometimes cold; sometimes it brings clouds and sometimes it drives away clouds; sometimes it causes pleasant gusts to blow and sometimes disastrous windstorms; sometimes it brings beneficial rains and sometimes there is drought; in short, there are different 'kinds of winds which blow in their own time, and every kind serves one or the other purpose. This arrangement is the proof of a dominant Power, for which neither it can be impossible to bring life into existence, nor to obliterate it, nor to re-create it after having annihilated it. Likewise, this arrangement is also a proof of a supreme wisdom about which only a foolish man could think that all this was being done for fun, without any higher object in view. As against this wonderful system man is so helpless that he can neither cause a favourable wind to blow for himself, nor can prevent a disastrous cyclone from blowing on himself. However shameless, obstinate and stubborn he may be, the wind does at one time or another remind him that a Mighty Sovereign is ruling over him, Who can turn this principal means of his life into a cause of blessing for him or into a cause of ruin for him whenever He so likes, and man does not have the power to prevent or avert any of His decisions. (For further explanation, see E.N. 7 of Al-Jathiyah, E.N.'s 1 to 4 of Adh-Dhariyat).
Source : Al-Mursalat Verse 7: Indeed, what you are promised is to occur.