We used to greet the Prophet ﷺ during prayer and he would return our greeting, until we returned from the land of Abyssinia. I greeted him but he did not respond, and I was overcome with worry from every side. I sat down, and when he finished the prayer he said, "Allah decrees of His command whatever He wills, and He has now decreed that there be no speaking during the prayer."
أخبرنا الحسين بن حريث قال حدثنا سفيان عن عاصم عن أبي وائل
كنا نسلم على النبي ﷺ فيرد علينا السلام حتى قدمنا من أرض الحبشة فسلمت عليه فلم يرد علي فأخذني ما قرب وما بعد فجلست حتى إذا قضى الصلاة قال إن الله عز وجل يحدث من أمره ما يشاء وإنه قد أحدث من أمره أن لا يتكلم في الصلاة
[Its isnad is hasan] Abu Dawud narrated it in "Prayer," chapter on returning the greeting during prayer, no. 924, from the hadith of Asim bin Abu Najud with this wording, and it is also found in Sunan al-Kubra, no. 559. Bukhari mentioned it as a suspended report in his Sahih, "Tawhid," chapter 42, before no. 7522, where Sufyan bin Uyayna stated explicitly that he had heard it directly.