وَحَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ لاَ يَحْتَلِبَنَّ أَحَدٌ مَاشِيَةَ أَحَدٍ بِغَيْرِ إِذْنِهِ أَيُحِبُّ أَحَدُكُمْ أَنْ تُؤْتَى مَشْرُبَتُهُ فَتُكْسَرَ خِزَانَتُهُ فَيُنْتَقَلَ طَعَامُهُ وَإِنَّمَا تَخْزُنُ لَهُمْ ضُرُوعُ مَوَاشِيهِمْ أَطْعِمَاتِهِمْ فَلاَ يَحْتَلِبَنَّ أَحَدٌ مَاشِيَةَ أَحَدٍ إِلاَّ بِإِذْنِهِ ‏"‏ ‏.‏

Malik related to me from Nafi from Ibn Umar that the Messenger ofAllah, may Allah bless him and grant him peace, said, "No one shouldmilk someone else's cow without his permission. Would any of you likesomeone to come to his apartment, break into his larder, and take hisfood? The udders of cows guard their food for their owners, so no oneshould milk someone else's cow without his permission." Translation Not Available

Book reference: Muwatta Imam Malik Book 54 Hadith 1782
Web reference: Muwatta Imam Malik Book 54 Hadith 17