عَنِ النُّعْمَانِ بْنِ بَشِيرٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: إِنِّي أَعْلَمُ النَّاسِ أَوْ كَأَعْلَمِ النَّاسِ بِوَقْتِ صَلَاةِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمِ لِلْعِشَاءِ، كَانَ يُصَلِّيهَا بَعْدَ سُقُوطِ الْقَمَرِ فِي اللَّيْلَةِ الثَّالِثَةِ مِنْ أَوَّلِ الشَّهْرِ
It is narrated from Sayyiduna Nu’man bin Bashir (may Allah be pleased with him), who says: I am the most knowledgeable about the time of the ‘Isha prayer of the Messenger of Allah (peace and blessings be upon him). At the beginning of the month, after the setting of the crescent moon of the third night, he (peace and blessings be upon him) would perform this prayer.