Explain the Biblical parable of the talents that Milton refers to in his poem "When I consider how my light is spent".

In the poem commonly known as "When I consider how my
light is spent," John Milton refers to a Biblical parable found in the books of Matthew
and Luke.  In this parable, a man was preparing to leave on a lengthy trip and entrusted
three of his servants with differing amounts of money in his absence. One servant
received five talents, one received two talents, and the final servant received one
talent.

Each of the first two servants chose to invest the
money entrusted to him and ended up doubling the amount given him.  The last servant,
who had been allotted one talent, chose to hid the money, rather than risk or venture
anything.

When the "lord of those servants" returned, he
called them to him and was thrilled with the cunning of the first two servants.  Because
they had acted wisely, he promoted them.  The servant who had hidden his money told his
master that he had been frightened and hidden the money.  The master was furious and
ordered that he have the talent taken from him and given "unto him which hath ten
talents."