Judges 16:5-9

So the governors of the Philistines came up to her and said to her, “Entice him, and see where his great strength lies and how we can overpower him so that we may bind him to humble him. Then we will each give you 1,100 pieces of silver.”

So Delilah said to Samson, “Please tell me where your great strength lies, and how you can be bound to humble you.”

And Samson said to her, “If they bind me with seven fresh animal tendons that have not been dried, then I will become weak and be like any other man.”

Then the governors of the Philistines brought up to her seven fresh animal tendons that had not been dried, and she bound him with them.

Now she had men prepared for an ambush in an inner room. And she said to him, “The Philistines are upon you, Samson!” But he tore the tendons to pieces just like a thread of flax is torn apart when it comes too close to fire. So his strength was not discovered.