The Roman Missal: Proper of Saints, February (English) 17

1[February 24, or 25 in Leap Year. St Matthias, Apostle.—Double of the Second Class.]
2Introit. Ps. cxxxviii. To me thy friends, O God, are made exceedingly honourable: their principality is exceedingly strengthened. Ps. Lord, thou hast proved me, and known me; thou hast known my sitting down, and my rising up. Glory, &c.
3Prayer. Deus qui beatum. O God, who didst associate blessed Matthias to the company of thy apostles, grant, we beseech thee, that by his intercession, we may ever experience thy tender mercy towards us. Through our Lord, &c.
4Lesson. Acts i. 15—26. In those days, Peter rising up in the midst of the brethren, said: (now the number of persons together was about a hundred and twenty,) Men and brethren, the scripture must needs be fulfilled which the Holy Ghost spoke before by the mouth of David concerning Judas, who was the leader of them that apprehended Jesus: who was numbered with us, and had obtained part of this ministry. And he indeed hath possessed a field of the reward of iniquity; and, being hanged, burst asunder in the midst; and all his bowels gushed out. And it became known to all the inhabitants of Jerusalem, so that the same field was called in their tongue Haceldama, that is to say, the field of blood. For it is written in the book of Psalms, Let their habitation become desolate, and let there be none to dwell therein: and his bishoprick let another take. Wherefore of these men who have companied with us, all the time that the Lord Jesus came in and went out among us, beginning from the baptism of John until the day wherein he was taken up from us, one of these must be made a witness with us of his resurrection. And they appointed two, Joseph called Barsabas, who was surnamed Justus, and Matthias. And praying they said, Thou, Lord, who knowest the hearts of all men, shew whether of these two thou hast chosen, to take the place of this ministry and apostleship, from which Judas hath by transgression fallen, that he might go to his own place. And they gave them lots, and the lot fell upon Matthias, and he was numbered with the eleven apostles.
5Gradual. Thy friends, O God, are exceedingly honourable; their principality is exceedingly strengthened.—I will number them, and they shall be multiplied above the sand.
6Tract. Thou hast given him his soul's desire, and hast not withholden from him the will of his lips.—For thou hast prevented him with blessings of sweetness.—Thou hast set on his head a crown of precious stones.
7[Gospel. I praise thee, O Father, as page 510. The Credo is said.]
8Offertory. Thou shalt make them princes over all the earth: they shall remember thy name, O Lord, in every progeny and generation.
9Secret. May the prayer of thy holy apostle Matthias accompany the sacrifice which we offer to thy name, O Lord, by which mayest thou grant us to be purified and defended. Through our Lord, &c.
10[Preface for Apostles, as in the Ordinary, page 22.]
11Communion. You who have followed me shall sit on seats judging the twelve tribes of Israel.
12Postcom. Præsta quæsumus. Grant, we beseech thee, O Almighty God, that by these holy mysteries which we have received, through the intercession of thy blessed apostle Matthias, we may obtain pardon and peace. Through our Lord, &c.