The Origin of Tefillah (Prayer)
Tzaddikim felt the need to speak to Hashem and did so in their own words.  Avraham initiated prayer in the morning, Yitzchak initiated prayer in the afternoon, and Yaakov initiated prayer in the evening.  When the Torah was given, it became a mitzvah to pray to Hashem each day. 
The Shemoneh Esrei
Prayer in one’s own words remained the practice of klal Yisrael until the time of the Anshei Knesses HaGedolah, the Men of the Great Assembly, at the beginning of the period of the Second Beis HaMikdash. At this time, Jews were returning to Eretz Yisrael, bringing with them the new languages they had absorbed in exile. They were no longer able to express themselves in pure Lashon HaKodesh, and in these circumstances, the Anshei Knesses HaGedolah prepared the first fixed text for tefillah in clear and simple Lashon HaKodesh. 
They composed a tefillah of eighteen berachos (blessings), with blessings of praise to start, then requests, and finally blessings of praise and leave-taking to end. The requests were requests for klal Yisrael as a nation, but within each berachah one could still add one’s personal requests.  This prayer became known as the Shemoneh Esrei, meaning “the Eighteen,” the central tefillah of the Jewish people.
Later, during the time of the Tannaim, an additional berachah was added, called “Birkas Haminim” (against heretics). This additional berachah was instituted at Yavneh under the leadership of Rabban Gamliel.  The blessing was composed in response to the threats of Jewish heretics – the Sadducees, Boethusians, and Essenes – who tried to lead klal Yisrael astray. The Shemoneh Esrei was now made up of nineteen berachos – three first berachos, thirteen middle berachos, and three final berachos – however, it still retained the name “Shemoneh Esrei,” the Eighteen. 
In this way, the Shemoneh Esrei became set, the principle part of every tefillah of klal Yisrael. Around the Shemoneh Esrei, the Anshei Knesses HaGedolah built the remainder of each tefillah, which is said every morning, afternoon, and evening.
 The Talmud calls prayer, “The service of the heart” (Ta’anis 2a).
 Talmud: Berachos 26b; Midrash Rabbah, Bereishis 68:9.
 Rambam, Sefer Ahavah, Hilchos Tefillah 1:1-2.
 Rambam: Sefer Ahavah, Hilchos Tefillah 1:4.
 One’s personal requests can be added to any of the middle thirteen berachos, most often to the berachah, Refa‘einu.
 Birkas HaMinim begins: “And for the slanderers let there be no hope.”
 Talmud: Berachos 28b
OlamiResources.com is greatly appreciative to Rabbi Akiva Aaronson for sharing three free chapters from his important recent sefer, The Foundation of Judaism. The sefer offers educators and their students an overview of basic concepts of Judaism and Jewish life, focusing on emunah, Jewish history, lashon HaKodesh, Tefillah, Torah study, Torah transmission, the Jewish calendar, Shabbos and Kashrus. Torah U’Mesorah stated that this sefer offers “a lucid and concise resource for those who teach any age.” Hamodia said the book is “a veritable goldmine.” This week we have published the second of three installments – the chapter titled, “The Foundation of Tefillah.” Please click here to purchase The Foundation of Judaism. For further information and Rabbi Aaronson’s additional publications, please see Akiva-Aaronson.com.