It is the scene where Cassius notices that the two eagles
that have accompanied their army have now flown away. In their place are ravens and crows to which
the army sees as a bad omen. This causes
a break down in morale among the troops as Cassius and Brutus wonder about
their fates. Brutus swears that he will
not be taken prisoner regardless of what happens today.
The purpose of these words is to give off the impression of averageness, whether of a substance, event, or person. It shows that the thing in question is quite readily available to anyone, and that it is nothing to marvel at. These words give off the impression of "nothing to see here" essentially.
