Song of Ascents
Song of Ascents is a title given to fifteen of the Psalms, 120–134 (119–133 in the Septuagint and the Vulgate), that each starts with the ascription Shir Hama'aloth (Hebrew: שיר המעלות, meaning "Song of Ascent"). They are also variously called Gradual Psalms, Songs of Degrees, Songs of Steps or Pilgrim Songs.
Four of them (122, 124, 131 and 133) are claimed in their ascriptions to have been written by David, and one (127) by Solomon, the rest being anonymous. Some modern scholars do not believe that these ascriptions can be taken literally, although they give evidence that helps in dating of the Psalms and identifying their original use.
Many scholars believe these psalms were sung by the worshippers as they ascended up the road to Jerusalem to attend the three pilgrim festivals (Deuteronomy 16:16) or by the kohanim (priests) as they ascended the fifteen steps to minister at the Temple in Jerusalem.
They were well suited for being sung, by their poetic form and the sentiments they express. "They are characterized by brevity, by a key-word, by epanaphora [i.e., repetition], and by their epigrammatic style.... More than half of them are cheerful, and all of them hopeful."
Christian liturgy 
The liturgical use of these psalms came into Christianity through its Jewish roots. The form of the Scriptures used in the Early Church, at least so far as the Hebrew Bible was concerned, was primarily the Septuagint. In the Septuagint, these psalms are numbered 119–133.
Many early hermits observed the practice of reciting the entire Psalter daily, coenobitic communities would chant the entire Psalter through in a week, so these psalms would be said on a regular basis, during the course of the Canonical hours.
Eastern Christianity 
In the Eastern Orthodox Church and those Eastern Catholic Churches which follow the Byzantine Rite, the Songs of Degrees (Greek: anabathmoi) make up the Eighteenth Kathisma (division of the Psalter), and are read on Friday evenings at Vespers throughout the liturgical year. The Kathisma is divided into three sections (called stases) of five psalms each.
During Great Lent the Eighteenth Kathisma is read every weekday (Monday through Friday evening) at Vespers, and on Monday through Wednesday of Holy Week. In the Slavic usage this Kathisma is also read from the apodosis of the Exaltation of the Cross up to the forefeast of the Nativity of Christ, and from the apodosis of Theophany up to the Sunday of the Prodigal Son. The reason for this is that the nights are longer in winter, especially in the northern latitudes, so during this season three Kathismas will be chanted at Matins instead of two, so in order to still have a reading from the Psalter at Vespers, the Eighteenth Kathisma is repeated.
At Matins on Sundays and feast days throughout the year, special hymns called anavathmoi (Greek: άναβαθμοί, from βαθμός, 'step'; Slavonic: stepénnyi) are chanted immediately before the prokeimenon and Matins Gospel. These anavathmoi are compositions based upon the Hymns of Degrees, and are written in the eight tones of Byzantine chant. The Anavathmoi for each tone consists of three stases or sets of verses (sometimes called antiphons), except for Tone 8 which has four stases. On Sundays, the anavathmoi are chanted according to the tone of the week; on feast days which do not fall on Sunday, the Avavathmoi almost always consist of the first stasis in Tone 4 (based on Psalm 128).
Symbolically, the anabathmoi are chanted as a reminder that Christians are ascending to the Heavenly Jerusalem, and that the spiritual intensity of the service is rising as we approach the reading of the Gospel.
Western Christianity 
The Western Daily Office was strongly influenced by the Rule of St. Benedict, where these psalms are assigned to Terce, Sext and None on weekdays. Over the centuries, however, various schedules have been used for reciting the psalms. In the modern Liturgy of the Hours of the Roman Catholic Church, the Gradual Psalms are used in several ways:
- Psalms 120-127 and 129-131 are scheduled throughout the four-week Psalter for use at Vespers; 119, 128, and 132 are scheduled for use for Daytime Prayer, and 133 is scheduled for Night Prayer.
- Psalms 119-127 are broken into three parts, to be used as the complementary Psalmody for those who pray three daytime offices separately as Terce, Sext, and None, rather than one office of Daytime Prayer.
- They are used as the sole Psalmody at daytime prayer on solemnities, except for certain solemnities of the Lord and during the octave of Easter and those solemnities falling on Sunday.
Judaism: present day 
It is also traditional for some Jews to place a copy of Psalm 121 in the labor and delivery room to promote an easy labor by asking God for mercy. As well, it is placed on the baby's carriage and in the baby's room to protect the child and surround them in learning and with holy objects.
- Nassar, Seraphim (1938), Divine Prayers and Services of the Catholic Orthodox Church of Christ (3rd ed.), Englewood NJ: Antiochian Orthodox Christian Archdiocese of North America (published 1979), pp. 1086–7
- Kallistos (Ware), Archimandrite; Mary, Mother (1969), The Festal Menaion, London: Faber and Faber (published 1984), p. 549, ISBN 0-571-11137-8
- "Plan for the Distribution of the Psalms in the Office", General Instruction for the Liturgy of the Hours, The Catholic Liturgical Library, February 2, 1971, retrieved 2008-05-18
- Shir HaMaalos in the Hospital from Sichos in English
- Ask Moses: Why do people place the "Shir Hamaalot" Psalm near a baby's crib?