We used to greet one another during the prayer, but then we were told that the prayer keeps one fully occupied.
حدثنا أحمد بن سعيد الدارمي حدثنا النضر بن شميل حدثنا يونس بن أبي إسحق عن أبي إسحق عن أبي الأحوص
كنا نسلم في الصلاة فقيل لنا إن في الصلاة لشغلا
[Sahih, marfu] * Abu Ishaq narrated with an "an" formula, as mentioned before, no. 46. Busiri said, this chain is sahih, its narrators are reliable. Bukhari related it, no. 1199, 1216, 3875, and Muslim, no. 538, from the hadith of Amash, from Ibrahim, from Alqama, from Ibn Masud, with the same wording as marfu, but longer than this.