It was narrated that ‘Attab, the freed slave of Hurmuz, said:“I heard Anas bin Malik say: ‘We gave our pledge to the Messenger of Allah (ﷺ) on the basis that we would listen and obey. He (ﷺ) said: “As much as you can.”
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، حَدَّثَنَا شُعْبَةُ، عَنْ عَتَّابٍ، - مَوْلَى هُرْمُزَ - قَالَ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ، يَقُولُ بَايَعْنَا رَسُولَ اللَّهِ صلى الله عليه وسلم عَلَى السَّمْعِ وَالطَّاعَةِ فَقَالَ " فِيمَا اسْتَطَعْتُمْ " .
IbnMaja
The Chapters on Jihad • Hadith 2868