beyond control,
And the frenzy of her own soul,
Again mow down the shoot.

At this point in the play, the whole family is in one big mess!  Antigone is in big trouble with her uncle, King Creon, because she defied his decree and buried her brother Polynices who had been a traitor to the city-state of Thebes.  Ismene, Antigone's sister, is in trouble too, because she's trying to defend Antigone.  Haemon, the young man who is engaged to marry Antigone, is in hot water for the same reason.  And Creon is in a fix too.  Should he order the execution of his own niece, and her fiance?  Or should he let her go, and let it be known that traitors, and people who sympathize with them, will be dealt with lightly?

The ancient Greek way of explaining such problems was to say that someone had angered the gods.  In this case, the Chorus suggests that the anger goes back to Oedipus, who is the father of Antigone, Ismene, and the two dead brothers: Polyneces the traitor, and Eotocles the hero.  Oedipus, as you may know, committed a couple of whopper mistakes: he murdered his father and he married his mother.  The Chorus suggests that all the hard times that are plaguing the characters in this play are because the gods are angry at their father, Oedipus.

Now let's look at some of the Chorus's text:

a) Happy the man whose cup of life is free
From taste of evil ! If Heaven's influence shake Them, no ill but follows,
Till it overtake them,
All generations of his family ;

Roughly translated, this means: Happy is the person who has done nothing evil to anger the gods -- because if you do anger them, ill (bad) consequenses will catch up with you and all the generations of your family.

b) son with sire entangled, without end,
And by some God smitten without remedy

A son will be tangled up with his father (sire) and will be hit (smitten) by the gods without any chance of healing.

c) a  light of late had spread
O'er the last surviving root
In the house of Oedipus ;

A punishment has spread to the last remaining descendants of Oedipus.  (I'm not sure why the punishment is referred to as "a light"; maybe it means a fire.)

An ancient play such as Antigone has been printed in many different editions, so it's difficult to know exactly which comments of the chorus you are referring to.  I'm going to assume that you're interested in the first two major  appearances of the chorus.

a) The first time the chorus appears, it is to introduce the background to the play's plot.  The Chorus explains that the city of Thebes has just defeated an invasion led by Polynices, who is the son of the Thebean king, Creon.  They describe how Polynices was defeated in hand-to-hand combat by his own brother, Eteocles.  The Chorus encourages the people of Thebes to go to the temples and thank the gods for their victory, and to "dance through the night" to celebrate.

All of this helps us to understand the conversation at the beginning of the play between Antigone and Ismene, the sisters of Polynices and Eteocles.  They discuss how their father, King Creon, has given an "honorable burial" to  Eteocles, the hero of Thebes; regarding Polynices, who is a traitor against his home city of Thebes, the king has decreed that "no one may bury or mourn him, but must see him unlamented,unburied, a sweet find for birds to feast upon."

(It might have seemed logical to us to have had the Chorus come on at the beginning of the play and give the background.  This, however, was never done in ancient Greek plays.  Perhaps it was more interesting to begin the play with the actual characters talking to each other.)

b) The second major appearance by the chorus occurs after a guard has informed Creon that someone (it turns out to be Antigone) has disobeyed the king and buried the body of Eteocles.  In this speech, the Chorus is not so concerned with providing background; rather, it delivers a philosophical observation, which is one of the other common roles of the Chorus in ancient Greek drama.

The Chorus here reflects on the "wondrous" abilities of mankind:

  He rules
with devices the mountain haunts of the wild animal
and tames the shaggy-necked horse
with a yoke on its back
and the tireless mountain bull. 
He taught himself language and wind-like
thought and city-ruling urges,
how to flee the slings of frost
under winter's clear sky
and the arrows of stormy rain, ever-resourceful.
Against no possibility is he at a loss.

Although man has wonderful abilities, he must be careful not to do wrong:

but there is no city [there is no place to escape to] 
for one who participates in what is wrong.

Anyone who disobeys the will of the gods will be punished.

Here also, the Chorus's statement has the additional purpose of introducing the continuation of the play, which describes how Antigone, and others, are punished by the gods for participating in "what is wrong."