When it is said
Pray it when you feel angry words rising, or before a conversation you dread.
It can be prayed whole, or its third verse alone, “Set a guard, LORD, over my mouth”, as a short prayer before you speak.
Where it comes from
Author by tradition
The Church’s evening psalm
An old book of church rules, the Apostolic Constitutions, tells Christians to gather every morning and evening to sing psalms and pray. They were to say Psalm 63 in the morning and this psalm in the evening. Its second verse, where prayer rises like incense and lifted hands are the evening offering, is what made it the psalm for that hour.
Apostolic Constitutions, in Ante-Nicene Fathers, volume 7; G. V. Shann, Euchology (1891), notes on Vespers
Where the Orthodox sing it
At Vespers the Orthodox still sing it under the name “Lord, I have cried”. At the Liturgy of the Presanctified Gifts, after the readings from Genesis and Proverbs, the choir sings “Let my prayer be set forth”, and the guard over the mouth is one of the verses sung with it.
G. V. Shann, Euchology (1891), the All-Night Vigil; Isabel F. Hapgood, Service Book (1906), the Liturgy of the Presanctified Gifts
What the words mean
What the Church sings in verses 4 and 5
The Orthodox sing this psalm from the Greek Old Testament, which reads differently from the Hebrew in places. In verse 4 the Greek asks that the heart not turn to evil words “to make excuses for sins”. In verse 5 it asks that the oil of a sinner never anoint the head, where the Hebrew speaks of a righteous man’s correction as oil.
The Scripture in it
I call upon You, O LORD; come quickly to me. Hear my voice when I call to You. May my prayer be set before You like incense; my uplifted hands, like the evening offering. Set a guard, O LORD, over my mouth; keep watch at the door of my lips. Do not let my heart be drawn to any evil thing or take part in works of wickedness with men who do iniquity; let me not feast on their delicacies. Let the righteous man strike me; let his rebuke be an act of loving devotion. It is oil for my head; let me not refuse it. For my prayer is ever against the deeds of the wicked.
But my eyes are fixed on You, O GOD the Lord. In You I seek refuge; do not leave my soul defenseless. Keep me from the snares they have laid for me, and from the lures of evildoers.
Bible text: Berean Standard Bible, public domain.