Psalm 91

Psalm 91 (Greek numbering: Psalm 90), referred to by its Latin title Qui habitat (after its first line, "Whoso dwelleth under the defence of the Most High"), is known as the Psalm of Protection. As a religious song, this Psalm is commonly invoked in times of hardship. The author of this psalm is unknown.

The apotropaic usage of Psalm 91 is also corroborated by midrash Bamidbar Rabbah 12:3 which recounts the story of Moses’ ascent to the Mount Sinai during which he was assaulted by a band of hostile angels wishing to prevent him from acquiring the Torah. According to the midrash, the patriarch defended himself by singing the words of Psalm 91, the so called “psalm of plagues”. The first two verses are abundant in the divine names: “The one sitting in the cover of Elyon, in the shadow of Shaddai will dwell, says to Yahveh: my refuge and my fortress, my Elohim, I will trust in him.” Moses acknowledged the protective strength of the biblical poem concluding that “by means of his name I shall repel the {demons} and the angels of destruction”.

The devil quotes verses 11 and 12 of this psalm during the temptation of Christ in Matthew 4:6 and Luke 4:10-11.

In Western Christianity it is often sung or recited during services of Compline.

In the Revised Common Lectionary (Year C) the psalm is appointed for the first Sunday in Lent, linking it to the temptation of Christ, where the devil quotes this psalm.

In the medieval Western Church it was included in the readings for Good Friday.

In Eastern Orthodoxy it is used in the prayers of the Sixth Hour, at Great Compline, and also in the Memorial Service for the departed (Pannikhida).

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