This essay is evidence of changes in Emerson's later life. As you probably know, Emerson's earlier life is evidenced by true optimism (such as can be seen in "Nature" and other works); however, later in life Emerson read a lot of literature from Asia. Oriental literature as a whole focuses a lot on fate and its use in society. This greatly affected Emerson, and he felt a need to deal with this subject in his later essays. This particular essay is his attempt to deal with that subject.
The first concept Emerson deals with here is obstacles. Emerson indicates that these obstacles in life are unavoidable and that all people will experience them. Ironically, here Emerson feels the need to defend all of the theses of his earlier life by stating the vast importance of "liberty." Because, from here on out, his views do seem quite opposite from the views of the "young" Emerson. Emerson goes further and says that the ideal in life is to bring both liberty and fate into balance.
Now Emerson begins with the answer to your true question: the different meanings of fate according to Hinduism, Calvinism, Greek tragedy, etc. Suddenly, Emerson portrays nature as rough and believes in predestination! An important aspect of fate is that it can be found in both "matter and mind." It therefore encompasses all aspects of human life. He does say something very important here, though:
Intellect annuls fate.
So those that hold tight to Emerson's earlier ideas can make a sigh of relief after hearing him say that. Still, Emerson says that the only way to release oneself from the "bondage" of fate is to cling to ones morals and, in fact, one's "moral sentiment," and in this way you can be released.
Further, Emerson does finally exhibit that a person can affect fate according to will because an event doesn't have to do with the interior of the soul, only the exterior. Fate, then, cannot affect the interior of the soul. In this way, Emerson explores the idea of cause and effect to the life of the average human. And Emerson, then, ends his essay on a positive note reflecting that balance (discussed earlier) of liberty and fate. Emerson now believes trust to be most important in order for a person to become the best version of himself. Note here the ultimate balance of fate and liberty:
Let us build altars to the Blessed Unity which holds nature and souls in perfect solution.
As a result, this is not really considered one of the representative works of Emerson, but is a sort of aberration that only the most philosophical students study to further their knowledge on Emersonian ideas and thought. However, if one takes anything away from this essay it is that fate and liberty need to be balanced.