Sahih Al Bukhari (626)

عن طاوس قال حدثني أعلمهم بذاك يعني ابن عباس رضي الله عنهما "أن النبي (صلى الله عليه وسلم) خرج إلى أرض تهتز زرعا فقال لمن هذه فقالوا اكتراها فلان فقال أما إنه لو منحها إياه كان خيرا له من أن يأخذ عليها أجرا معلوما"

Tawus reported that he was told by the most learned one amongst them (i.e. Ibn `Abbas) that the Prophet (peace be upon him) went towards some land which was flourishing with vegetation and asked to whom it belonged. He was told that such and such a person took it on rent. The Prophet (peace be upon him) said: "It would have been better (for the owner) if he had given it to him gratis rather than charging him a fixed rent.