The 'act' is divided into two main scenes, the common or unifying theme being 'trial by physical strength'.
Harapha is the 'strong man' of the Philistines. He disdains to fight with the blinded Samson, and takes pleasure in mocking the fact that Samson 'hast need of much washing to be touched' (l.1107). Harapha has no intention of fighting Samson, he has come to taunt the fallen hero. He suggests that Samson's achievement was based on black magic ('black enchantments') of 'some magician's art' rather than strength (ll.1130-35). Samson provides resolute answer that his strength is God-given - 'my trust is in the living God who gave me / At my nativity this strength' (ll.1140-41). Again, Samson acknowledges his punishment, or his 'fall', as his own doing:
'All these indignities, for such they are
From thine, these evils I deserve and more,
Acknowledge them from God inflicted on me
Justly'
(ll.1168-71)
Harapha insults Samson, aksing how can he serve his God being a 'A murderer, a revolter, and a robber' (l.1180). Harapha talks of Samson's earlier deeds at Ascalon, and of the submission of Samson's people to the Philistines. Samson rebukes Harapha's comment regarding the justification for Danite submission to the Philistines. He states that it was forceful conquest: 'My nation was subjected to your lords. / It was the force of conquest; force with force / Is well ejected when the conquered can.' (ll.1205-7) Samson reiterates his vocation:
'I was no private but a person raised
With strength sufficient and command from heaven
To free my country; if their servile minds
Me their deliverer sent would not receive,
But to their masters gave me up for nought,
The unworthier they; whence to this day they serve.'
(ll.1211-16)
Samson challenges Harapha to combat a second time (ll.1233-35). Samson demonstrates self-control in face of insult, revealing his patience and temperance.
In the second scene the Philistian Officer continues the trial by physical strength. The Officer has been sent to Samson to command him to appear at the feast to honour Dagon to perform a feat of physical strength. Samson retains his self-control; he reminds the Officer as a Hebrew, he is thus forbidden from entering the temple: 'Thous know'st I am an Hebrew, therefore tell them, / Our law forbids at their religious rites / My presence; for that cause I cannot come' (ll.1319-21). The Officer tells Samson that refusing to appear at the temple will greatly anger the Philistian magistrates. The Chorus tells Samson that the Officer may exacerbate matters by distorting the prisoner's answer and refusal to appear at the temple. Samson reveals that his physical strength is returning.
While refusing to follow the Philistian lords' command to appear at the temple, Samson accedes to going voluntarily: 'If I obey them, / I do it freely' (ll.1372-73). Samson and the Chorus stress the idolatry and inferiority of the Philistines, remarking they are 'vile, contemptible, ridiculous' (l.1361) and 'Idolatrous, uncircumcised, unclean' (l.1364). Samson announces to his bethren that he is to leave and go to the temple. Before he leaves, Samson reassures them that he remains pious towards God and his nation. The Chorus cannot comprehend Samson's action - they do not know that he is once again acting in response to God's will. He stresses that 'I begin to feel / Some rousing motions in me which dispose / To something extraordinary in my thoughts.' The hero is quick to assert that at the temple Samson 'Nothing to do, be sure, that may dishonour / Our law, or stain my vow of Nazarite.' Samson provides awareness of the importance of his attendance at the festival in the temple; the hero remarks 'This day will be remarkable in my life / By some great act, or of my days the last' (ll.1388-89).
This, according to the rules of classical drama, is the last time that we see Samson before the end of the tragedy. Samson leaves with the Officer.