Origin

During the temple service during the days of the temple, a series of thanksgiving prayers were recited. These have since become incorporated into daily prayer.

Placement in service

While Ashkenazi Judaism recited these following Barukh She'amar

Barukh She'amar

Barukh she'amar , is the opening blessing to pesukei dezimra.Barukh sheamar contains 87 words. This is the gematria of the Hebrew word paz meaning "refined gold."-Purpose:...

, Sephardi Judaism recites the prayers beforehand. The reason for this given by Ashkenazi Judaism is that the current world is called the World of Yezirah, a world that is not repaired, and therefore one that does not receive light from itself. Sephardi Judaism states that these prayers are recited before Barukh She'amar because the prayers receive tikkun from assiyah, as they follow Kaddish

Kaddish

Kaddish is a prayer found in the Jewish prayer service. The central theme of the Kaddish is the magnification and sanctification of God's name. In the liturgy different versions of the Kaddish are used functionally as separators between sections of the service...

.

Hodu

Hodu Lashem Kir'u Bishmo, or "Hodu" (from ). This is the longer one of the thanksgiving prayers. It was first recited by David

David

David was the second king of the united Kingdom of Israel according to the Hebrew Bible and, according to the Gospels of Matthew and Luke, an ancestor of Jesus Christ through both Saint Joseph and Mary...

 after he recovered the ark from the Philistines

Philistines

Philistines , Pleshet or Peleset, were a people who occupied the southern coast of Canaan at the beginning of the Iron Age . According to the Bible, they ruled the five city-states of Gaza, Askelon, Ashdod, Ekron and Gath, from the Wadi Gaza in the south to the Yarqon River in the north, but with...

. Following this event, it became a standard prayer.

Psalm 100

Psalm 100

Psalm 100

Psalm 100 is part of the biblical Book of Psalms. It may be used as a canticle in the Anglican liturgy of Morning Prayer, when it is referred to by its incipit as the Jubilate or Jubilate Deo...

 is the shorter prayer. The psalm expresses thanks to God for all the miracles that happen to us each day in total oblivion, as we are routinely in danger without even knowing it.

Psalm 100 is omitted by Ashkenazi Jews on Shabbat

Shabbat

Shabbat is the seventh day of the Jewish week and a day of rest in Judaism. Shabbat is observed from a few minutes before sunset on Friday evening until a few minutes after when one would expect to be able to see three stars in the sky on Saturday night. The exact times, therefore, differ from...

, Yom Tov, the Eve of Yom Kippur

Yom Kippur

Yom Kippur , also known as Day of Atonement, is the holiest and most solemn day of the year for the Jews. Its central themes are atonement and repentance. Jews traditionally observe this holy day with a 25-hour period of fasting and intensive prayer, often spending most of the day in synagogue...

, the Eve of Passover

Passover

Passover is a Jewish holiday and festival. It commemorates the story of the Exodus, in which the ancient Israelites were freed from slavery in Egypt...

, and the intermediate days

Chol HaMoed

Chol HaMoed, a Hebrew phrase meaning "weekdays [of] the festival" , refers to the intermediate days of Passover and Sukkot. During Chol HaMoed the usual restrictions that apply to the Biblical Jewish holidays are relaxed, but not entirely eliminated...

 of Passover. Sephardic Judaism

Sephardic Judaism

Sephardic law and customs means the practice of Judaism as observed by the Sephardi and Mizrahi Jews, so far as it is peculiar to themselves and not shared with other Jewish groups such as the Ashkenazim...

 does however recite the psalm on Shabbat.

On Shabbat and Yom Tov, it is omitted because offering Thanksgiving is voluntary, and therefore is not done on days with Shabbat-like restrictions.

On the Eve of Passover, it is omitted because during the temple service, one may not be able to finish eating the offering, which was chametz

Chametz

Chametz, also Chometz, and other spellings transliterated from , are leavened foods that are forbidden on the Jewish holiday of Passover. According to Jewish law, Jews may not own, eat or benefit from chametz during Passover...

, before the time in which it was forbidden to eat chametz.

On Passover, it is omitted because of its chametz content.

On the Eve of Yom Kippur, it is omitted because one may not be able to finish the contents before the fast sets in.