What is the ruling on returning an insult with an insult when exposed to it by the mother-in-law?

If your mother-in-law insults you, you are permitted to respond in kind without aggression, based on the Almighty’s saying: "So whoever has assaulted you, then assault him in like manner as he assaulted you." However, you are not permitted to lie to her, even if she lies to you, because one sin cannot be met with another. Forgiveness is preferable unless it leads to corruption, and responding to evil with goodness brings affection and protects against the evil of Satan.