No less far from the truth is the dangerous error of those who endeavor to deduce from the mysterious union of us all with Christ a certain unhealthy quietism. They would attribute the whole spiritual life of Christians and their progress in virtue exclusively to the action of the Divine Spirit, setting aside and neglecting the collaboration which is due from us. No one, of course, can deny that the Holy spirit of Jesus Christ is the one source of whatever supernatural powers enters into the Church and its members. For ‘The Lord will give grace and glory’ as the Psalmist says (Ps 83:12). But that men should persevere constantly in their good works, that they should advance eagerly in grace and virtue, that they should strive earnestly to reach the heights of Christian perfection and at the same time to the best of their power should stimulate others to attain the same goal, – all this the heavenly Spirit does not will to effect unless they contribute their daily share of zealous activity. ‘For divine favors are conferred not on those who sleep, but on those who watch,’ as Saint Ambrose says (Expos. Evang. sec. Luc., IV, 49; PL 15, 1626). For if in our mortal body the members are strengthened and grow through continued exercise, much more truly can this be said of the social Body of Jesus Christ in which each individual member retains his own personal freedom, responsibility, and principles of conduct. For that reason he who said: ‘I live, now not I, but Christ liveth in me’ (Gal 2:20) did not at the same time hesitate to assert: ‘His (God’s) grace in me has not been void, but I have labored more abundantly than all they: yet not I, but the grace of God with me’ (1Cor 15:10). (Pius XII. Encyclical Mystici Corporis Christi, no. 87, June 29, 1943)

Again, (amen) I say to you, if two of you agree on earth about anything for which they are to pray, it shall be granted to them by my heavenly Father. For where two or three are gathered together in my name, there am I in the midst of them. (Mt 18: 19-20)

Thus, the life of prayer is the habit of being in the presence of the thrice-holy God and in communion with him. (Catechism of the Catholic Church, no. 2565)

The Lord leads all persons by paths and in ways pleasing to him, and each believer responds according to his heart’s resolve and the personal expressions of his prayer. However, Christian Tradition has retained three major expressions of prayer: vocal, meditative, and contemplative. They have one basic trait in common: composure of heart. This vigilance in keeping the Word and dwelling in the presence of God makes these three expressions intense times in the life of prayer. (Catechism of the Catholic Church, no. 2699)

To accomplish so great a work, Christ is always present in His Church, especially in her liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, ‘the same now offering, through the ministry of priests, who formerly offered himself on the cross’ ( Council of Trent, Session XXII, Doctrine on the Holy Sacrifice of the Mass, c. 2), but especially under the Eucharistic species. By His power He is present in the sacraments, so that when a man baptizes it is really Christ Himself who baptizes (cf. Saint Augustine, Tractatus in Ioannem, 6, n. 7). He is present in His word, since it is He Himself who speaks when the holy scriptures are read in the Church. He is present, lastly, when the Church prays and sings, for He promised: ‘Where two or three are gathered together in my name, there am I in the midst of them’ (Mt 18:20). Christ indeed always associates the Church with Himself in this great work wherein God is perfectly glorified and men are sanctified. The Church is His beloved Bride who calls to her Lord, and through Him offers worship to the Eternal Father. (Vatican Council II, Constitution on the Sacred Liturgy Sacrosanctum concilium, No. 7, December 4, 1963)

But it is His will, besides, that the worship He instituted and practiced during His life on earth shall continue ever afterwards without intermission. For he has not left mankind an orphan. He still offers us the support of His powerful, unfailing intercession, acting as our ‘advocate with the Father’ (cf. 1 Jn 2:1). He aids us likewise through His Church, where He is present indefectibly as the ages run their course: through the Church which He constituted ‘the pillar of truth’ (cf. 1Tim 3:15) and dispenser of grace, and which by His sacrifice on the cross, He founded, consecrated and confirmed forever (cf. Boniface IX, Ab origine mundi; Callistus III, Summus Pontifex; Pius II, Triumphans Pastor; Innocent XI, Triumphans Pastor). (Pius XII. Encyclical Mediator Dei, No. 18, November 20, 1947)

But the chief element of divine worship must be interior. For we must always live in Christ and give ourselves to Him completely, so that in Him, with Him and through Him the heavenly Father may be duly glorified. (Pius XII. Encyclical Mediator Dei, no. 24, November 20, 1947)

It is an unquestionable fact that the work of our redemption is continued, and that its fruits are imparted to us, during the celebration of the liturgy, notable in the august sacrifice of the altar. Christ acts each day to save us, in the sacraments and in His holy sacrifice. By means of them He is constantly atoning for the sins of mankind, constantly consecrating it to God. Sacraments and sacrifice do, then, possess that ‘objective’ power to make us really and personally sharers in the divine life of Jesus Christ. Not from any ability of our own, but by the power of God, are they endowed with the capacity to unite the piety of members with that of the head, and to make this, in a sense, the action of the whole community. (Pius XII. Encyclical Mediator Dei, No. 29, November 20, 1947)

The unbloody immolation at the words of consecration, when Christ is made present upon the altar in the state of a victim, is performed by the priest and by him alone, as the representative of Christ and not as the representative of the faithful. (Pius XII. Encyclical Mediator Dei, No. 92, November 20, 1947)

To this lofty dignity of the Church’s prayer, there should correspond earnest devotion in our souls. For when in prayer the voice repeats those hymns written under the inspiration of the Holy Ghost and extols God’s infinite perfections, it is necessary that the interior sentiment of our souls should accompany the voice so as to make those sentiments our own in which we are elevated to heaven, adoring and giving due praise and thanks to the Blessed Trinity; ‘so let us chant in choir that mind and voice may accord together’ (Saint Benedict, Regula Monachorum, c. 19). It is not merely a question of recitation or of singing which, however perfect according to norms of music and the sacred rites, only reaches the ear, but it is especially a question of the ascent of the mind and heart to God so that, united with Christ, we may completely dedicate ourselves and all our actions to Him. (Pius XII. Encyclical Mediator Dei, No. 145, November 20, 1947)

‘For in the Church,’ it is said, ‘God hath set apostles, prophets, teachers’(1Cor 12:28), and all the other means through which the Spirit works; of which all those are not partakers who do not join themselves to the Church, but defraud themselves of life through their perverse opinions and infamous behavior. For where the Church is, there is the Spirit of God; and where the Spirit of God is, there is the Church, and every kind of grace; but the Spirit is truth. (Saint Irenaeus of Lyons. Against Heresies, Book III, Ch. 24)

The Psalmist reminds us that God was in constant touch with his people through Moses and Aaron, his mediators, and through Samuel, his prophet. He spoke and was heard, he punished offenses but also forgave. The sign of his presence among his people was ‘his footstool’, namely, the throne of the Ark of the Temple of Zion (cf. vv. 5-8). (John Paul II. General audience, November 27, 2002)

‘I thought on these things, and poured out my soul above myself’ (Psalm 41:4). When would my soul attain to that object of its search, which is ‘above my soul’, if my soul were not to ‘pour itself out above itself’? For were it to rest in itself, it would not see anything else beyond itself; and in seeing itself, would not, for all that, see God. (Saint Augustine of Hippo. Exposition on Psalm 42, no.7)

For when I was ‘pouring out my soul above myself,’ in order to reach my God, why did I do so? ‘For I will go into the place of Your Tabernacle’. For I should be in error were I to seek for my God without ‘the place of His tabernacle’. ‘For I will go into the place of Your wonderful tabernacle, even unto the house of God’. (Saint Augustine of Hippo. Exposition on Psalm 42, no.8)

For there are already many things that I admire in ‘the tabernacle’. See how great wonders I admire in the tabernacle! For God’s tabernacle on earth is the faithful; I admire in them the obedience of even their bodily members: that in them ‘Sin does not reign so that they should obey its lusts; neither do they yield their members instruments of unrighteousness unto sin; but unto the living God in good works’ (Rom 6:12-13). (Saint Augustine of Hippo. Exposition on Psalm 42, no.8)

It is the priest, more than any other, who is bound to obey scrupulously the command of Christ: We ought always pray (Lk 18:1). […] How numerous are the opportunities of turning to God in prayer which present themselves daily to the soul which is eager for its own sanctification and the salvation of others! Anguish of soul, the persistent onslaught of temptation, our lack of virtue, slackness and failure in our works, our many offenses and negligences, fear of the divine judgment, all these should move us to approach the Lord with tears, in order to obtain help from him and also to increase without difficulty the treasure of our merit in his eyes. (Pius X. Apostolic Exhortation Haerent animo, August 4, 1908)