رسولُ اللَّهِ صلى اللَّه عليه وآله : لا يَحِلُّ لامرئٍ مِن مالِ أخيهِ شيءٌ إلّا بطِيبِ نَفْسٍ مِنهُ . كنز العمّال : 30345 .
The Prophet (SAWA) said, 'It is unlawful for anyone to use the property of his brother except by his consent.' Kanz al-Ummal, no. 30345