If you continue to read this post, a follow-up on the one before, you can gently tell the priest who preaches on the invisible Church that he is wrong. It is our duty to point these things out as gently, but as firmly as we can. This heresy is rife in some areas. I have had comments indicating this, sadly. Another BIG posting day by necessity....
Holiness begins from Christ; and Christ is its cause. For no act conducive to salvation can be performed unless it proceeds from Him as from its supernatural source. "Without me," He says, "you can do nothing." If we grieve and do penance for our sins if, with filial fear and hope, we turn again to God, it is because He is leading us. Grace and glory flow from His inexhaustible fulness. Our Savior is continually pouring out His gifts of counsel, fortitude, fear and piety, especially on the leading members of His Body, so that the whole Body may grow ever more and more in holiness and integrity of life. When the Sacraments of the Church are administered by external rite, it is He who produces their effect in souls. He nourishes the redeemed with His own flesh and blood and thus calms the turbulent passions of the soul; He gives increase of grace and prepares future glory for souls and bodies. All these treasures of His divine goodness He is said to bestow on the members of His Mystical Body, not merely because He, as the Eucharistic Victim on earth and the glorified Victim in heaven, through His wounds and His prayers pleads our cause before the Eternal Father, but because He selects, He determines, He distributes every single grace to every single person "according to the measure of the giving of Christ." Hence it follows that from our Divine Redeemer as from a fountainhead "the whole body, being compacted and fitly joined together, by what every joint supplieth according to the operation in the measure of every part, maketh increase of the body, into the edifying of itself in charity." 
And, we have not even gotten into the meat of the encyclical. Here is more:
60. And now, Venerable Brethren, We come to that part of Our explanation in which We desire to make clear why the Body of Christ, which is the Church, should be called mystical. This name, which is used by many early writers, has the sanction of numerous Pontifical documents. There are several reasons why it should be used; for by it we may distinguish the Body of the Church, which is a Society whose Head and Ruler is Christ, from His physical Body, which, born of the Virgin Mother of God, now sits at the right hand of the Father and is hidden under the Eucharistic veils; and, that which is of greater importance in view of modern errors, this name enables us to distin guish it from any other body, whether in the physical or the moral order.
And, here is the cruncher.
64. From what We have thus far written, and explained, Venerable Brethren, it is clear, We think, how grievously they err who arbitrarily claim that the Church is something hidden and invisible, as they also do who look upon her as a mere human institution possession a certain disciplinary code and external ritual, but lacking power to communicate supernatural life. On the contrary, as Christ, Head and Exemplar of the Church "is not complete, if only His visible human nature is considered..., or if only His divine, invisible nature..., but He is one through the union of both and one in both ... so is it with His Mystical Body" since the Word of God took unto Himself a human nature liable to sufferings, so that He might consecrate in His blood the visible Society founded by Him and "lead man back to things invisible under a visible rule."
65. For this reason We deplore and condemn the pernicious error of those who dream of an imaginary Church, a kind of society that finds its origin and growth in charity, to which, somewhat contemptuously, they oppose another, which they call juridical. But this distinction which they introduce is false: for they fail to understand that the reason which led our Divine Redeemer to give to the community of man He founded the constitution of a Society, perfect of its kind and containing all the juridical and social elements - namely, that He might perpetuate on earth the saving work of Redemption, - was also the reason why He willed it to be enriched with the heavenly gifts of the Paraclete. The Eternal Father indeed willed it to be the "kingdom of the Son of his predilection;" but it was to be a real kingdom in which all believers should make Him the entire offering of their intellect and will, and humbly and obediently model themselves on Him, Who for our sake "was made obedient unto death." There can, then, be no real opposition or conflict between the invisible mission of the Holy spirit and the juridical commission of Ruler and Teacher received from Christ, since they mutually complement and perfect each other - as do the body and soul in man - and proceed from our one Redeemer who not only said as He breathed on the Apostles "Receive ye the Holy Spirit," but also clearly commanded: "As the Father hath sent me, I also send you;" and again: "He that heareth you, heareth me."