It is narrated from Qasim bin Muhammad who says that Aisha (may Allah be pleased with her) used to give zakat from our wealth and trade was conducted with it in Bahrain.
Hadith Referenceمسند الإمام الشافعي / كتاب الزكاة / 718
Hadith Takhrijاسناده صحیح اخرجه البيهقى فى المعرفة السنن والآثار (2267) ۔ وعبد الرزاق (6983) وابن ابي شيبة (10118) ، (10114)۔