Abu Abd al-Rahman al-Sulami narrates: Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) used to teach us to pray four rak'ahs after Jumu'ah, until we heard the saying of Sayyiduna Ali (may Allah be pleased with him): "Pray six rak'ahs!" Abu Abd al-Rahman said: So we pray six rak'ahs. Ata narrates: Abu Abd al-Rahman used to pray two rak'ahs first, and then four rak'ahs after that.
Al-Tabarani recorded it in al-Mu'jam al-Kabir; Ata bin al-Sa'ib is thiqah (trustworthy), but his memory became confused (ikhtilat) later on.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 3193