SALVATION IS NOT POSSIBLE WITHOUT PURIFICATION OF SOUL!
VERSES NO.1-10
The sura starts with oaths for referring to another important point. Generally, in Quran, oaths signify the importance of the issue for which it has been sworn, as well as the importance of what is sworn by.
Sun has the most important and critical role in the life of man and all other earthly creatures. It is the source of light and heat, and many other critical resources like winds, rains, plants, oil and coal originate from it.
The full moon, day, night, the heavens the earth and man's soul are all among the great wonders of creation.
The important issue is that whoever purifies his soul, will be successful and prosperous and whoever taints it, will fail.