Explanation:

- The idiom "Grease someone’s palm" means to give someone money or a favor to influence their decision or actions. This is often done in the form of a bribe to expedite a process or gain favor.

- Option 1: Go to battle

- This means to prepare to fight or argue over an issue. It does not relate to bribery.

- Option 2: Put in hard work

- This suggests making a strong effort or laboring diligently, unrelated to influencing someone with money.

- Option 3: Bribe someone

- This accurately captures the essence of the idiom, which is to secretly exchange money for favorable treatment or outcomes.

- Option 4: Be jealous of someone

- This indicates envy towards another's success or possessions, not connected to bribery.