The Messenger of Allah ﷺ turned his face toward us when he stood for prayer, before saying the takbir, and said, "Straighten your rows and stand close together, for I see you from behind my back."
أخبرنا علي بن حجر أنبأنا إسمعيل عن حميد
أقبل علينا رسول الله ﷺ بوجهه حين قام إلى الصلاة قبل أن يكبر فقال أقيموا صفوفكم وتراصوا فإني أراكم من وراء ظهري
Bukhari narrated it in Sahih Bukhari, in the Adhan, chapter "The Imam Facing the People When Straightening the Rows," no. 719, from the hadith of Humayd Tawil, with this wording, and he made explicit the hearing, and the hadith is also in Kubra, no. 888.