I have hauled sand
I have carried salt
But nothing is heavier than debt.
-Ahiqar

Neither a borrower nor a lender be;
For loan oft loses both itself and friend.
-Shakespeare

The rich rules over the poor,
and the borrower is the slave of the lender
-Proverbs 22:7 (ESV)

Painful to a sensitive man
are abuse at home and insults
from his creditors.
-Sirach 29:28 (NAB)

Debt is the slavery of the free.
-Publius Syrus

Update! 9/21/07
Ok, so this quote isn’t ancient, but it’s really good:

What can be added to the happiness of a man who is in health, out of
debt, and has a clear conscience?
– Adam Smith (1723-1790)