Yosef Karo, Translation:Shulchan Aruch — Orach Chaim 48Reciting Daily and Sabbath Sacrificial Passages
“ And those who are exacting have practiced to shake at the time that we read the Torah as an illustration of the Torah that was given with trembling, and so too at the time that we pray, because of "all my bones will say to you, Lord who is like You?" ”
