Musnad Ahmad 578
It was narrated that ‘Abdullah bin Zurair said:
I entered upon `Ali bin Abi Talib (رضي الله عنه) - Hasan said: On the day of (Eid) al-Adha - and he brought some khazeerah (a dish made from small pieces of meat, broth and flour) to us. I said: May Allah guide you! Why don`t you make a dish for us from these ducks, for Allah, may He be glorified and exalted, has blessed us with a great deal of bounty. He said: O son of Zurair, I heard the Messenger of Allah (ﷺ)  say: “It is not permissible for the caliph to take more from the wealth of Allah than two dishes: one from which he and his family eat and one that he offers to the People.”
حَدَّثَنَا حَسَنٌ، وَأَبُو سَعِيدٍ مَوْلَى بَنِي هَاشِمٍ قَالَا حَدَّثَنَا ابْنُ لَهِيعَةَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ هُبَيْرَةَ، عَنْ عَبْدِ اللَّهِ بْنِ زُرَيْرٍ، أَنَّهُ قَالَ دَخَلْتُ عَلَى عَلِيِّ بْنِ أَبِي طَالِبٍ رَضِيَ اللَّهُ عَنْهُ قَالَ حَسَنٌ يَوْمَ الْأَضْحَى فَقَرَّبَ إِلَيْنَا خَزِيرَةً فَقُلْتُ أَصْلَحَكَ اللَّهُ لَوْ قَرَّبْتَ إِلَيْنَا مِنْ هَذَا الْبَطِّ يَعْنِي الْوَزَّ فَإِنَّ اللَّهَ عَزَّ وَجَلَّ قَدْ أَكْثَرَ الْخَيْرَ فَقَالَ يَا ابْنَ زُرَيْرٍ إِنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ لَا يَحِلُّ لِلْخَلِيفَةِ مِنْ مَالِ اللَّهِ إِلَّا قَصْعَتَانِ قَصْعَةٌ يَأْكُلُهَا هُوَ وَأَهْلُهُ وَقَصْعَةٌ يَضَعُهَا بَيْنَ يَدَيْ النَّاسِ‏.‏