The Apostles received from the Great High Priest before His Ascension, a commission to execute the various functions of the priestly office, to baptize[7], to teach[8], to consecrate and offer the Holy Eucharist[9], and to absolve[10]; besides a general and comprehensive promise that all their official acts should be confirmed by Him, in the words, "Lo, I am with you alway, even unto the end of the world[11]." [Sidenote: but not exerted till after Pentecost.] We do not, however, find that this commission was acted on by the Apostles before the day of Pentecost; the Saviour's will was, that it should, so to {7} speak, lie dormant until the seal of the Holy Spirit was impressed upon it. During the days of expectation which followed our Lord's Ascension, we read that the holy company who were gathered together in the "upper room," "continued with one accord in prayer and supplication[12];" but we have no mention of any celebration of the Holy Eucharist, whilst immediately after the Descent of the Holy Ghost we are told of their daily continuance in "the Breaking of the Bread[13]." Section 3. _The Day of Pentecost._ [Sidenote: A.D. 33. Participation of the Blessed Trinity in the works of Creation, the Incarnation, and the Foundation of the Church.] As the Three Holy Persons of the Ever-blessed Trinity had shared in the work of the First Creation of the world, the Father speaking by the Eternal Word, and the Holy Spirit brooding over what before was lifeless: and as in the work of the Incarnation the Father had sent the Son to take upon Him our human nature through the operation of the Holy Ghost: so, in the Foundation of the Church, the Power of the Holy Spirit co-operated no less than the Will of the Father and the Life-giving Grace of the Son. {8} [Sidenote: The waiting at Jerusalem.] The Apostles had received from their ascending Lord a command to await in the City of Jerusalem this "Power from on High," which was to be sent upon them[14]. We can easily see the fitness of this injunction, when we remember that they were about to become the founders of the New Jerusalem, the true "City of God" in which the many "glorious things spoken[15]" by the Old Testament Prophets were to have their performance to a certain extent even in this life, but fully and perfectly in the Life to come. [Sidenote: St. Matthias chosen.]