Mishnah — Seder Zeraim, Tractate BerakhotChapter 1…
“ Rabbi Yehoshua says: [One may recite the Shema] until three hours [of the day] , for such is the way of the sons of kings, to arise at the third hour. If one recites [the Shema] later than this, he has not lost out, [but rather is] like one who reads the Torah. ”
