וְשִׁנַּנְתָּ֣ם לְבָנֶ֔יךָ וְדִבַּרְתָּ֖ בָּ֑ם בְּשִׁבְתְּךָ֤ בְּבֵיתֶ֙ךָ֙ וּבְלֶכְתְּךָ֣ בַדֶּ֔רֶךְ וּֽבְשָׁכְבְּךָ֖ וּבְקוּמֶֽךָ׃
и будешь усердно учить их своим детям и говорить о них, когда сидишь в доме твоем, и когда идешь по дороге, и когда ложишься и когда поднимаешься.
Sefer HaMitzvot
That which He commanded us to read Shema in the evening and morning and he said [in the torah] "and you shall speak of them". And the laws of this of this mitzvah were already explained in tractate Berakhot (page 21) and there it explains that reading the Shema is a biblical commandment. And in the Tosefta is states "just as when the torah was given the reading of the shema was established, so too the sages established times for prayer", this means to say that the times for prayer are not biblical, rather the obligation of prayer itself is biblical, as we explained, and the sages, may their memory be a blessing, organized times for them. And this is the concept that was stated (TB Berakhot 26b) "The prayers were established according to the Tamid offerings", which means to say that they established times [for prayer] according to the times for the sacrifices. And women are not obligated in this commandment. (Parshat Va'etchanan; Rambam Sefer Ahava, Hilchot Keriat Shema Chapter 1).