Muwatta Imam Malik Book of Judgements, Hadith 12

Yahya said that Malik had said from Da'ud ibn al-Husayn that he heard Abu Ghatafan ibn Tarif al-Muriyi say, "Zayd ibn Thabit al-Ansari and Ibn Muti had a dispute about a house which they shared. They went to Marwan ibn al-Hakam who was the Amir of Madina. Marwan decided that Zayd ibn Thabit must take an oath on the mimbar. Zayd ibn Thabit said, 'I swear to it where I am.' Marwan said, 'No, by Allah! only in the place of sorting out claims (i.e. the mimbar).' Zayd ibn Thabit began to take an oath that his right was true, and he refused to take an oath near the mimbar. Marwan ibn al-Hakam began to wonder at that."
Malik said, "I do not think that anyone should be made to take an oath near the mimbar for less than a fourth of a dinar, and that is three dirhams."

قَالَ يَحْيَى قَالَ مَالِكٌ عَنْ دَاوُدَ بْنِ الْحُصَيْنِ، أَنَّهُ سَمِعَ أَبَا غَطَفَانَ بْنَ طَرِيفٍ الْمُرِّيَّ، يَقُولُ اخْتَصَمَ زَيْدُ بْنُ ثَابِتٍ الأَنْصَارِيُّ وَابْنُ مُطِيعٍ فِي دَارٍ كَانَتْ بَيْنَهُمَا إِلَى مَرْوَانَ بْنِ الْحَكَمِ وَهُوَ أَمِيرٌ عَلَى الْمَدِينَةِ فَقَضَى مَرْوَانُ عَلَى زَيْدِ بْنِ ثَابِتٍ بِالْيَمِينِ عَلَى الْمِنْبَرِ . فَقَالَ زَيْدُ بْنُ ثَابِتٍ أَحْلِفُ لَهُ مَكَانِي . قَالَ فَقَالَ مَرْوَانُ لاَ وَاللَّهِ إِلاَّ عِنْدَ مَقَاطِعِ الْحُقُوقِ . قَالَ فَجَعَلَ زَيْدُ بْنُ ثَابِتٍ يَحْلِفُ أَنَّ حَقَّهُ لَحَقٌّ . وَيَأْبَى أَنْ يَحْلِفَ عَلَى الْمِنْبَرِ - قَالَ - فَجَعَلَ مَرْوَانُ بْنُ الْحَكَمِ يَعْجَبُ مِنْ ذَلِكَ . قَالَ مَالِكٌ لاَ أَرَى أَنْ يُحَلَّفَ أَحَدٌ عَلَى الْمِنْبَرِ عَلَى أَقَلَّ مِنْ رُبُعِ دِينَارٍ وَذَلِكَ ثَلاَثَةُ دَرَاهِمَ .