The Chorus discusses Samson's background and describes his various militaristic accomplishments:
Ran on embattled armies clad in iron, And, weaponless himself, Made arms ridiculous, useless the forgery Of brazen shield and spear, the hammered cuirass, Chalybean-tempered steel, and frock of mail Adamantean proof; ... Then with what trivial weapon came to hand, The jaw of a dead ass, his sword of bone, A thousand foreskins fell (lines 129-134, 142-4)
Although he is great, the Chorus points out that, through his blindness (actual and metaphorically), he is a prisoner:
Thou art become (O worst imprisonment!) The Dungeon of thy self; thy soul (Which men enjoying sight oft without cause complain) Imprisoned now indeed, In real darkness...