The opening section of Matins/3 - Psalm 3: the rubrics

In the aforesaid winter season, there is first the versicle Domine labia mea aperies et os meum annuntiabit laudem tuam to be said three times; then must follow the third psalm and the Gloria; then the ninety-fourth psalm to be chanted with an antiphon, or at any rate to be chanted. Let the hymn follow next…

Rule of St Benedict, chapter 9

Psalm 3: the rubrics

A key difference between the Roman and Benedictine Offices is that the later includes not one but two invitatory psalms each day.

The first of these, Psalm 3, is said without antiphon, or 'in directum'.

According to the Liber Responsorialis, the psalm tone is the same as is used at Lauds for Psalm 66.

You sit after the first verse is finished, and stand again in time for the Gloria Patri which is added, as usual,  to the end of the psalm.

Psalmus 3  3:1 Dómine, quid multiplicáti sunt qui tríbulant me? * multi insúrgunt advérsum me. 3:2 Multi dicunt ánimæ meæ: * Non est salus ipsi in Deo ejus. 3:3 Tu autem, Dómine, suscéptor meus es, * glória mea, et exáltans caput meum. 3:4 Voce mea ad Dóminum clamávi: * et exaudívit me de monte sancto suo. 3:5 Ego dormívi, et soporátus sum: * et exsurréxi, quia Dóminus suscépit me. 3:6 Non timébo míllia pópuli circumdántis me: * exsúrge, Dómine, salvum me fac, Deus meus. 3:7 Quóniam tu percussísti omnes adversántes mihi sine causa: * dentes peccatórum contrivísti. 3:8 Dómini est salus: * et super pópulum tuum benedíctio tua. V. Glória Patri, et Fílio, * et Spirítui Sancto. R. Sicut erat in princípio, et nunc, et semper, * et in sǽcula sæculórum. Amen.

Psalm 3 3:1 Why, O Lord, are they multiplied that afflict me? * many are they who rise up against me. 3:2 Many say to my soul: * There is no salvation for him in his God. 3:3 But thou, O Lord art my protector, * my glory, and the lifter up of my head. 3:4 I have cried to the Lord with my voice: * and he hath heard me from his holy hill. 3:5 I have slept and taken my rest: * and I have risen up, because the Lord hath protected me. 3:6 I will not fear thousands of the people, surrounding me: * arise, O Lord; save me, O my God. 3:7 For thou hast struck all them who are my adversaries without cause: * thou hast broken the teeth of sinners. 3:8 Salvation is of the Lord: * and thy blessing is upon thy people. V. Glory be to the Father, and to the Son, * and to the Holy Ghost. R. As it was in the beginning, is now, * and ever shall be, world without end. Amen.

For those wanting to hear how it sounds in Latin, you can find a version of it link although some of the pronunciation does not fully align with the ecclesiastical Latin norms.