(1) It is a positive commandment to pray every day, as it is written: "You shall worship the Lord your God" (Ex. 23:25). By tradition, they learned that this worship is prayer, as it says: "and to worship God with all of your heart" (Deut. 11:13)—the sages said what is worship of the heart? This is prayer. The number of prayers is not biblical, the form of prayer is not biblical, and prayer has no biblically fixed time.

MISHNAH Women, slaves and minors are exempt from reading the Shema' and from Tefillin; but they are under the obligation of Tefillah, Mezuzah and Grace after meals. GEMARA Why are the reading of the Shema' and Tefillin different [from the others] ? Because they are commands the observance of which depends upon a certain point of time, and women are exempt from all commands of this class. Tefillah, Mezuzah and Grace after meals, being commands the observance of which does not depend upon a certain point of time, are obligatory upon women. That the reading of the Shema' [is not obligatory upon women] is self-evident, because it is a command the observance of which depends upon a certain point of time, and women are exempt from all commands of this class! [Why, then, does the Mishnah mention it ?] Thou mightest say that since it contains a reference to the Kingdom of Heaven [it should be read by women] ; therefore it informs us [they are exempt]. And from Tefillin. This too is evident ! Thou mightest say that since Tefillin are to be compared with Mezuzah [they should be obligatory upon women] ; therefore it informs us [they are exempt]. But they are under the obligation of Tefillah ; [obviously] because this is prayer! [not translated] But thou mightest say that since it is written thereby, "Evening and morning and at noonday" (Ps. lv. 18), it is like a command the observance of which depends upon a certain point of time [and women are exempt]; therefore it informs us [the obligation is theirs].

(2) “A positive commandment” – So wrote the Rambam, who thinks that tefillah is a positive biblical commandment, as it is written, “and to serve God with all of your heart…” But biblically, it is sufficient to recite one prayer a day, in any formulation that one wishes. Therefore, most women have the practice of not praying regularly, because immediately after washing their hands in the morning they say some request, and this is biblically sufficient, and it is possible that the sages did not extend their obligation any further. But the Ramban thinks that tefillah is rabbinic, and this is the opinion of most decisors.