Jami` at-Tirmidhi 405
جامع الترمذي#405SahihZaid bin Arqam narrated:"We used to talk behind Allah's Messenger (S) during the Salat, a man among us would talk to his companions next to him until (the following) was revealed: And stand before Allah with obedience. (2:238) So we were ordered to be silent and prohibited from talking
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 2:258