Sahih Muslim 860
Sahih Muslim · Book 7: The Book of Prayer - Friday · Jumu`ah prayer is when the sun has passed its zenith
Iyas b. Salama b. Akwa' reported on the authority of his father, saying:
وَحَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ ، أَخْبَرَنَا هِشَامُ بْنُ عَبْدِ الْمَلِكِ ، حَدَّثَنَا يَعْلَى بْنُ الْحَارِثِ ، عَنْ إِيَاسِ بْنِ سَلَمَةَ بْنِ الأَكْوَعِ ، عَنْ أَبِيهِ ، قَالَ كُنَّا نُصَلِّي مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم الْجُمُعَةَ فَنَرْجِعُ وَمَا نَجِدُ لِلْحِيطَانِ فَيْئًا نَسْتَظِلُّ بِهِ .
We used to observe the Friday prayer with the Messenger of Allah (ﷺ), and when we returned we did not find the shadow of the walls in which we could take protection (from the heat of the sun).