Sirach 16:10

10 Nor the six hundred thousand footmen, who were gathered together in the hardness of their hearts.

Sirach 16:10 In-Context

8 Neither spared he the place where Lot sojourned, but abhorred them for their pride.
9 He pitied not the people of perdition, who were taken away in their sins:
10 Nor the six hundred thousand footmen, who were gathered together in the hardness of their hearts.
11 And if there be one stiffnecked among the people, it is marvel if he escape unpunished: for mercy and wrath are with him; he is mighty to forgive, and to pour out displeasure.
12 As his mercy is great, so is his correction also: he judgeth a man according to his works

The Brenton translation of the Septuagint is in the public domain.