Hadith 252
Sayyiduna Abdullah bin Mas'ud, may Allah be pleased with him, says: Before going to Habasha, during prayer we used to greet the Prophet, peace and blessings be upon him, and he would reply to us. When we returned from Habasha, I greeted the Prophet, peace and blessings be upon him, but he did not reply. So whoever was near or far from me caught hold of me, and I said: Has any new command come regarding me? Or has something new appeared in me? The Prophet, peace and blessings be upon him, said: "Ibn Mas'ud! It is not that. Allah creates whatever He wills from His commands. Now the new thing is that there should be no conversation during prayer."