Muwatta Malik · Hadith 314

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ دَاوُدَ بْنِ الْحُصَيْنِ، عَنِ ابْنِ يَرْبُوعٍ الْمَخْزُومِيِّ، أَنَّهُ قَالَ سَمِعْتُ زَيْدَ بْنَ ثَابِتٍ، يَقُولُ الصَّلاَةُ الْوُسْطَى صَلاَةُ الظُّهْرِ ‏.‏

Yahya related to me from Malik from Da'ud ibn al-Husayn that Ibn Yarbu al-Makhzumi said, "I heard Zayd ibn Thabit say, 'The middle prayer is the prayer of dhuhr

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).