Samson Agonistes draws on the story of Samson from the Old Testament, Judges 13-16; in fact it is a dramatisation of the story starting at Judges 16:23. The drama starts in medias res. Samson has been captured by the Philistines, had his hair, the container of his strength, cut off and his eyes cut out. Samson is "Blind among enemies, O worse than chains" (line 66).

Near the beginning of the play, Samson humbles himself before