In Julius Caesar, what does Cassius men when he says the following quote."A friend should bear his friend's infirmities... A friendly eye could...

This quote comes from Act IV scene 3, and is part of a
rather heated conversation that Brutus has with Cassius, where he accuses Cassius of not
supporting him because he did not send money to Brutus so he could pay for more legions
to support him. This scene is very important therefore as representing a major split in
their friendship and in the leadership of the rebel side led by
Brutus.

Therefore, Cassius is actually saying to Brutus
through these words that by accusing him of such deeds, he is denying their friendship
and not recognising the many ways in which Cassius has been a friend to Brutus
throughout the play. It is accusations such as these from Brutus that lead him to
threaten to commit suicide to prove his loyalty to Brutus.