The reason why credit card prosecution requires you to bring materials to a law firm is that the lawyer needs to evaluate and investigate the case and provide you with legal assistance and advice. The following are the materials you may need to bring:

1. Credit card statements, transaction records and other relevant documents proving your use of credit cards.

2. Lawyer consultation fee voucher or relevant agreement to determine the lawyer's agency fee.

3. If it involves reducing or modifying the repayment method, you may need to provide your personal financial information and income and expenditure.

4. You may need to provide other materials to prove your financial status and credit status, such as salary income certificate, house property certificate, insurance, etc. Bring these materials, and the lawyer will diagnose your credit card problem based on your situation and provide specific legal advice and solutions, such as negotiating a repayment plan with creditors, representing you in court prosecutions, etc. In short, if you are facing an overdue credit card or legal dispute, it is recommended that you seek consultation and help from a professional lawyer to better protect your interests and rights.