It’s not bad to be rich.  It is bad to be greedy and desire money, believing it will make your life more fulfilled.  Solomon, the richest king to ever live, gave some insight into this problem.

Whoever loves money never has enough;
    whoever loves wealth is never satisfied with their income.
    This too is meaningless. Ecclesiastes 5:10

            The rich person never has enough money, always wanting more.

As goods increase,
    so do those who consume them.
And what benefit are they to the owners
    except to feast their eyes on them? Ecclesiastes 5:11

            The rich person puts on weight with more money.  He also carries more burden on his spirit.

The sleep of a laborer is sweet,
    whether they eat little or much,
but as for the rich, their abundance
    permits them no sleep. Ecclesiastes 5:12

            The rich person can’t sleep well, worrying about all his riches.

wealth hoarded to the harm of its owners,
  or wealth lost through some misfortune,
so that when they have children
    there is nothing left for them to inherit. Ecclesiastes 5:13-14

As a rich person grabs more and more for himself, he has nothing to leave for others, especially his children.  He may not even have any relationship with those children.

Everyone comes naked from their mother’s womb,
    and as everyone comes, so they depart.
They take nothing from their toil
    that they can carry in their hands. Ecclesiastes 5:15

The rich person leaves this world with nothing, empty handed, possibly entering an afterlife of hopelessness and despair.

As everyone comes, so they depart,
    and what do they gain,
    since they toil for the wind?
All their days they eat in darkness,
    with great frustration, affliction and anger. Ecclesiastes 5:16-17

            The rich person lives a life of frustration and affliction and enters an after-life with more of the same if he didn't trust Jesus as his savior.