During the action of this play (or poem) Samson is in prison. While he is there, he is visited by many people. One of these is Dalila, his wife. The purpose of Dalila's visit is to apologize to Samson and to try to get him to forgive her.
Samson resists Dalila by refusing to believe that she is sincere. He does not believe that she truly has changed her ways. He tells her so in no uncertain terms, calling her a hyena, among other things.
Samson resists Dalila because he has grown (spiritually and emotionally) in the days since he fell for Dalila. Now he knows what is really important and this time he will not allow her to distract him from what he knows is right.