Isa bin Yonus bin Abi Ishaq عيسى بن يونس بن أبي إسحاق · Commercial Transactions (Kitab Al-Buyu)

I heard the Messenger of Allah (ﷺ) say: What is lawful is clear and what is unlawful is clear, but between them are certain doubtful things. I give you an example for this. Allah has a preserve, and Allah's preserve is the things He has declared unlawful. He who pastures (his animals) round the preserve will soon fall into it. He who falls into doubtful things will soon be courageous.

We used to lease land for what grew by the streamlets and for what was watered from them. The Messenger of Allah (ﷺ) forbade us to do that, and commanded us to lease if for gold or silver.