Which pattern means “the action will not be done to us”?

Negating the Imperfect with Lan and Lam: Subjunctive, Jussive and Full Paradigms

• لَنْ نَفْعَلَ
• لَمْ نُفْعَلْ
• لَنْ نُفْعَلَ
• لَمْ نَفْعَلْ