“These things write I unto thee, hoping to come unto thee shortly: but if I tarry long, that thou mayest know how thou oughtest to behave thyself in the house of God, which is the church of the living God, the pillar and ground of the truth. And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory.” 1 Timothy 3:14-16  (KJB)

I will give you some words for study and thought. It is a bit lengthy, but well worth reading.  Be blessed.

From Matthew Henry’s commentary on 1 Timothy 3:14-16…

He concludes the chapter with a particular direction to Timothy. He hoped shortly to come to him, to give him further directions and assistance in his work, and to see that Christianity was well planted, and took root well, at Ephesus; he therefore wrote the more briefly to him. But he wrote lest he should tarry long, that Timothy might know how to behave himself in the house of God, how to conduct himself as became an evangelist, and the apostle’s substitute. Observe,

1. Those who are employed in the house of God must see to it that they behave themselves well, lest they bring reproach upon the house of God, and that worthy name by which they are called. Ministers ought to behave themselves well, and to look not only to their praying and preaching, but to their behaviour: their office binds them to their good behaviour, for any behaviour will not do in this case. Timothy must know how to behave himself, not only in the particular church where he was now appointed to reside for some time, but being an evangelist, and the apostle’s substitute, he must learn how to behave himself in other churches, where he should in like manner be appointed to reside for some time; and therefore it is not the church of Ephesus, but the catholic church, which is here called the house of God, which is the church of the living God. Observe here, 1. God is the living God; he is the fountain of life, he is life in himself, and he gives life, breath, and all things to his creatures; in him we live, and move, and have our being, Act_17:25, Act_17:28. 2. The church is the house of God, he dwells there; the Lord has chosen Zion, to dwell there. “This is my rest, here will I dwell, for I have chosen it;” there may we see God’s power and glory, Psa_63:2.
2. It is the great support of the church that it is the church of the living God, the true God in opposition to false gods, dumb and dead idols.
3. As the church of God, it is the pillar and ground of truth; that is, either, (1.) The church itself is the pillar and ground of truth. Not that the authority of the scriptures depends upon that of the church, as the papists pretend, for truth is the pillar and ground of the church; but the church holds forth the scripture and the doctrine of Christ, as the pillar to which a proclamation is affixed holds forth the proclamation. Even to the principalities and powers in heavenly places is made known by the church the manifold wisdom of God, Eph_3:10. (2.) Others understand it of Timothy. He, not he himself only, but he as an evangelist, he and other faithful ministers, are the pillars and ground of truth; it is their business to maintain, hold up, and publish, the truths of Christ in the church. It is said of the apostles that they seemed to be pillars, Gal_2:9. [1.] Let us be diligent and impartial in our own enquiries after truth; let us buy the truth at any rate, and not think much of any pains to discover it. [2.] Let us be careful to keep and preserve it. “Buy the truth, and sell it not (Pro_23:23), do not part with it on any consideration.” [3.] Let us take care to publish it, and to transmit it safe and uncorrupted unto posterity. [4.] When the church ceases to be the pillar and ground of truth, we may and ought to forsake her; for our regard to truth should be greater than our regard to the church; we are no longer obliged to continue in the church than she continues to be the pillar and ground of truth.
4. But what is the truth which the churches and ministers are the pillars and grounds of? He tells us (1Ti_3:16) that without controversy great is the mystery of godliness. The learned Camero joins this with what goes before, and then it runs thus: “The pillar and ground of the truth, and without controversy great is the mystery of godliness.” He supposes this mystery to be the pillar, etc. Observe,

(1.) Christianity is a mystery, a mystery that could not have been found out by reason or the light of nature, and which cannot be comprehended by reason, because it is above reason, though not contrary thereto. It is a mystery, not of philosophy or speculation; but of godliness, designed to promote godliness; and herein it exceeds all the mysteries of the Gentiles. It is also a revealed mystery, not shut up and sealed; and it does not cease to be a mystery because now in part revealed. But,

(2.) What is the mystery of godliness? It is Christ; and here are six things concerning Christ, which make up the mystery of godliness. [1.] That he is God manifest in the flesh: God was manifest in the flesh. This proves that he is God, the eternal Word, that was made flesh and was manifest in the flesh. When God was to be manifested to man he was pleased to manifest himself in the incarnation of his own Son: The Word was made flesh, Joh_1:14. [2.] He is justified in the Spirit. Whereas he was reproached as a sinner, and put to death as a malefactor, he was raised again by the Spirit, and so was justified from all the calumnies with which he was loaded. He was made sin for us, and was delivered for our offences; but, being raised again, he was justified in the Spirit; that is, it was made to appear that his sacrifice was accepted, and so he rose again for our justification, as he was delivered for our offences, Rom_4:25. He was put to death in the flesh, but quickened by the Spirit, 1Pe_3:18. [3.] He was seen of angels. They worshipped him (Heb_1:6); they attended his incarnation, his temptation, his agony, his death, his resurrection, his ascension; this is much to his honour, and shows what a mighty interest he had in the upper world, that angels ministered to him, for he is the Lord of angels. [4.] He is preached unto the Gentiles. This is a great part of the mystery of godliness, that Christ was offered to the Gentiles a Redeemer and Saviour; that whereas, before, salvation was of the Jews, the partition-wall was now taken down, and the Gentiles were taken in. I have set thee to be a light of the Gentiles, Act_13:47. [5.] That he was believed on in the world, so that he was not preached in vain. Many of the Gentiles welcomed the gospel which the Jews rejected. Who would have thought that the world, which lay in wickedness, would believe in the Son of God, would take him to be their Saviour who was himself crucified at Jerusalem? But, notwithstanding all the prejudices they laboured under, he was believed on, etc. [6.] He was received up into glory, in his ascension. This indeed was before he was believed on in the world; but it is put last, because it was the crown of his exaltation, and because it is not only his ascension that is meant, but his sitting at the right hand of God, where he ever lives, making intercession, and has all power, both in heaven and earth, and because, in the apostasy of which he treats in the following chapter, his remaining in heaven would be denied by those who pretend to bring him down on their altars in the consecrated wafers. Observe, First, He who was manifest in flesh was God, really and truly God, God by nature, and not only so by office, for this makes it to be a mystery. Secondly, God was manifest in flesh, real flesh. Forasmuch as the children are partakers of flesh and blood, he also himself likewise took part of the same, Heb_2:14. And, what is more amazing, he was manifest in the flesh after all flesh had corrupted his way, though he himself was holy from the womb. Thirdly, Godliness is a mystery in all its parts and branches, from the beginning to the end, from Christ’s incarnation to his ascension. Fourthly, It being a great mystery, we should rather humbly adore it, and piously believe it, than curiously pry into it, or be too positive in our explications of it and determinations about it, further than the holy scriptures have revealed it to us

The Church is a visable entity seen in the local assembly through the Biblical teaching of its pastor, teachers, each faithful individual; also the worship of each congregation in singing of hymns, songs, spiritual songs, and being stewards in giving of our time, and God given resources.

Just to point out  one more thing.  Each of the  apostle Paul’s letters to churches – Corinth, Galatia, Ephesus, Philippi, Colossae, and Thessalonica – were written to the local congregation of that city.