How was Samson made captive in Samon Agonistes?

In both John Milton's Samson Agonistes and in the Bible, Samson is tricked by Delilah, who then cuts his hair, the source of his strength. Without his strength, Samson is then imprisoned by the Philistines until he regains his hair and strength and is able to break free, though he dies doing so.
Milton's interpretation of the Samson and Delilah story is that Samson betrayed God. By his physical desire for Delilah, he ignored the purpose for which God gave him his strength: to defeat enemies of Israel. By his pride in his strength, he allowed Delilah to get close to him and cut his hair. The final part of the play and poem show Samson being granted his strength again to regain his freedom. But because of Samson's earlier betrayal, his freedom is cut short by what Milton saw as his cathartic death.