Bava Kamma 32A

ואם עמד בעל קורה ⁠– חייב. ואם אמר לבעל חבית ״עמוד״⁠ – פטור.

But if the owner of the cross beam stopped, causing the jug to collide with the beam and break, the former is liable, since the latter had no way of anticipating that he would stop. And if he said to the owner of the jug: Stop, he is exempt from liability for breaking the jug.

היה בעל חבית ראשון ובעל קורה אחרון; נשברה חבית בקורה ⁠– חייב. ואם עמד בעל חבית ⁠– פטור. ואם אמר לבעל קורה: ״עמוד״⁠ – חייב. וכן זה בא בנרו וזה בפשתנו.

Conversely, if the owner of the jug was walking first and the owner of the cross beam last, and the jug was broken by the cross beam, the owner of the cross beam is liable. But if owner of the jug stopped, the owner of the cross beam is exempt from liability for breaking the jug. And if he said to the owner of the cross beam: Stop, the owner of the cross beam is liable. And similarly, these halakhot apply in a case where this one came with his lamp and that one came with his flax, and the lamp set fire to the flax.

גמ׳ בעא מיניה רבה בר נתן מרב הונא: המזיק את אשתו בתשמיש המטה, מהו? כיון דברשות קעביד ⁠– פטור, או דילמא, איבעי ליה לעיוני?

Talmud: Rabba bar Natan asked Rav Huna: With regard to one who causes injury to his wife during sex, what is the halakha? Is he liable to pay damages? Is it reasoned that since he is acting in a permitted manner he is exempt, or perhaps he should pay attention and be more careful?

אמר ליה, תניתוה: שלזה רשות להלך, ולזה רשות להלך.

Rav Huna said to Rabba bar Natan: You learned this halakha in the Mishnah concerning one person walking with a cross beam and another with a jug, which rules that the owner of the cross beam is exempt because this one had permission to walk and that one also had permission to walk. Similarly, since the husband has permission to have sex with his wife, if he injures her in the process he is exempt.