(44) باب الثَّالِثُ مِنَ الشُّرُوطِ فِيهِ الْمُزَارَعَةُ وَالْوَثَائِقُ
It was narrated from Hammad and Qatadah, concerning a man who said to another man:
"I will lease (something) from you until I reach Makkah for such and such a payment, and if I travel for a month or such and such -something that he named- I will give you such and such in addition." They did not see anything wrong with that, but they did not like it if he said: "If I travel for more than a month I will deduct such and such from your lease."
Reference: Sunan an-Nasa'i 3860
In-book reference: Book 35b, Hadith 4
English translation: Vol. 4, Book 35, Hadith 3891