Musannaf Ibn Abi Shaybah 5599 — Friday when the imam delays it until

Muslim says: In the time of Ziyad I used to sit with Masruq and Abu Ubaydah. When the time of the prayer came, both of them would stand and pray, then sit down. Then, when the muezzin called the adhan and the imam came out, they would stand and pray with him as well; and they would do the same at the time of Asr.