82. This passage (Ayats 66-72) is closely connected with the previous one. It tells man that if he wants to protect himself from the allurements, temptations and false promises of Satan who has been his avowed enemy from the day of his creation, he should recognize his real Lord and be steadfast in His obedience. Satan intends to prove that man is not worthy of the honor with which Allah has blessed him. Therefore if he follows any other way he cannot escape the snares of Satan.
In this passage, arguments of Tauhid have been put forward in order to make man steadfast in his faith and refrain from shirk.
83. That is, try to avail of the economic, social, educational and intellectual benefits which are provided by the sea voyages.
84. That is, this is a proof of the fact that your real nature knows no other Lord than Allah, and you feel in the depths of your hearts that He alone possesses the real power of every gain or loss. Had it not been so, man would never have invoked Allah at the time when he realized that no other helper could remove his misfortune.