It is narrated from Hazrat Samā’ bint Busr (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said: “Do not observe a fast on Saturday except for that which has been made obligatory upon you, and if any of you finds nothing to eat except a grape twig or the bark of a tree, then let him chew it.”
Hadith Referenceمسند احمد / مسند النساء / 27075
Hadith Gradingحکم دارالسلام:حديث ضعيف، وقد أعل بالاضطراب والمعارضة
A female companion (may Allah be pleased with her) asked the Prophet (peace and blessings be upon him) about the ruling of fasting on Saturday, so the Prophet (peace and blessings be upon him) said: "There is neither any special reward for it nor any sin."
Hadith Referenceمسند احمد / مسند النساء / 27076
Hadith Gradingحکم دارالسلام:إسناده ضعيف للاختلاف فيه على ابن لهيعة
It is narrated from Hazrat Samā’ bint Busr (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said: “Do not observe a fast on Saturday except for that which has been made obligatory upon you, and if any of you finds nothing to eat except a grape twig or the bark of a tree, then let him chew it.”
Hadith Referenceمسند احمد / مسند النساء / 27077
Hadith Gradingحکم دارالسلام:حديث ضعيف، وقد أعل بالاضطراب والمعارضة