Sayyiduna Abu Umamah (may Allah be pleased with him) narrates that the Prophet Muhammad (peace and blessings be upon him) said: "A borrowed item must be returned, and a borrowed (animal) will be returned. Whoever finds a pouch whose mouth is tied, it is not permissible for him to open it until he announces it."
Hadith Referenceصحیح ابن حبان / كتاب العارية / 5094
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الصحيحة» (611).فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده قوي