It is narrated from Hazrat Anas (may Allah be pleased with him) that we pledged allegiance to the Prophet (peace and blessings be upon him) on the condition of listening and obeying, and the Prophet (peace and blessings be upon him) added the restriction of "as much as you are able."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 12203
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا اسناد حسن