Silsilat al-Ahadith al-Sahihah

Sayyiduna Ali (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) commanded us to use the miswak and said: "When a servant stands for prayer, an angel comes to him and stands behind him, listening to the Noble Qur'an and drawing near. While listening to the Noble Qur'an, the angel draws so near that he places his mouth upon the mouth of the worshipper, and whatever verse the worshipper recites, the angel absorbs it within himself."