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 ﷺ عَلَى السَّمْعِ وَالطَّاعَةِ فَقَالَ " فِيمَا اسْتَطَعْتُمْ " .