וְהָי֞וּ הַדְּבָרִ֣ים הָאֵ֗לֶּה אֲשֶׁ֨ר אָנֹכִ֧י מְצַוְּךָ֛ הַיּ֖וֹם עַל־לְבָבֶֽךָ׃
И эти слова, которые я заповедую тебе сегодня, будут в твоем сердце;
Mishnah Berakhot
One who recites the Shema without causing it to be heard by his own ear, he has fulfilled his obligation. Rabbi Yose says: he has not fulfilled his obligation. If he recited it without pronouncing the letters succinctly, Rabbi Yose says he has fulfilled his obligation. Rabbi Judah says: he has not fulfilled his obligation. If he recites it out of order, he has not fulfilled his obligation. If he recites it and makes a mistake he goes back to the place where he made the mistake.