Here’s a picture of the tapestry that Jacob was working on:
The letters are Greek, and are:
theta xi omicron iota
tau omicron sigma alpha
delta omicron iota xi nu
omicron sigma alpha phi rho xi sigma iota
sigma eta sigma iota
mu xi nu omicron iota nu alpha zeta
I looked around and found a thread on Lostpedia, which states it roughly translates to:
“May the gods grant thee all that thy heart desires.”
Line 180 of The Odyssey, Book 6.
Hat tip to ClintAck.