Judaism has a defined set of liturgical prayers, Rabbi Langer said, to be recited by the faithful daily as well as on holidays and other occasions, with specific rules governing the invocation of God in blessings. This system of prayer arose and became obligatory following the Romans' 1st-century destruction of the Jerusalem Temple, where Jewish priests had made the ritual sacrifices prescribed in the Bible. Between the 2nd and 6th centuries, rabbinical writings on prayer were set down and were themselves canonized in the Talmud, the fundamental code of rabbinical law covering every aspect of Jewish life. Later Jewish communities and their leaders continually refined the details of the system they inherited to reflect their changing understanding of acceptable, meaningful and constructive worship, Rabbi Langer said. A major thesis of Rabbi Langer's book is that written law has taken precedence over popular custom in liturgical practices during times of mass migration or other upheavals in Jewish society.
Popular custom is much less firmly rooted.
When you have different people thrown together through intermarriage or through immigration from one country to the next, customs are shaken loose from their moorings. The more I learned, the more the tradition made sense. Now, I don't turn electricity on or off or drive during the Sabbath. The interest in prayer is what shapes people's spiritual lives.