The opening part is introductory. The holy Prophet, in fact, wanted to convey to his listeners what Gabriel had instilled into his heart at that time, but in order to give a special force to what he was going to tell, he, first, said that he had taught them all that there was to be taught concerning what was allowed and what was forbidden by the Shariat, and now he wanted to inform them of a thing just revealed to him by Gabriel which, in a nutshell, was that the sustenance of everyone had been determined beforehand and it was sure to reach him before he died, and, thus, a faithful bondsman should abstain from doing anything with regard to his livelihood that was displeasing to the Lord, and if there was a delay or hardship in it, even then he should not act in violation of a God-given law, but believing in the Almighty as the Great Provider of the daily bread, try to earn it only through fair and legitimate means as the favour of the Lord and His blessings could be gained only through submission.
Suppose a man is hungry and he has no money to buy food. At that moment, be sees someone who is fast asleep and the Devil tempts him to steal his goods and go and sell them and purchase for himself something to eat. It is for such an occasion that the sacred Prophet has taught that the bondsman should take it for granted that the provision that is to reach him shall reach him in any event. So, why should he incur the displeasure of the Lord; defile his soul and ruin his prospects in the world to come by committing theft? His aim and endeavour ought to be to earn his livelihood through honest means instead of a despicable act like stealing. The scope for earning an honest living is not limited by any means.