The Messenger of Allah ﷺ used to turn his face toward us before saying the opening takbir and would say, "Stand close together and straighten your rows, for I see you from behind my back."
حدثنا سليمان بن حيان أبو خالد عن حميد
كان رسول الله ﷺ يقبل علينا بوجهه قبل أن يكبر فيقول تراصوا واعتدلوا فإني أراكم من وراء ظهري
Its isnad is sahih. Sulayman bin Hayan Azdi is Abu Khalid Ahmar, who has some errors, and when he errs there is criticism of him, but his hadith is found in the collections of the group. The hadith itself is found in the collections of the group with similar wording. See 7329 and 11950.