It is not always that the author of a Biblical document clues us in directly as to his purposes for writing. We are happy to find that 1 Timothy has just such a statement.
Although I hope to come to you soon, I am writing you these instructions so that, if I am delayed, you will know how people ought to conduct themselves in God's household, which is the church of the living God, the pillar and foundation of the truth. Beyond all question, the mystery of godliness is great: He appeared in a body, was vindicated by the Spirit, was seen by angels, was preached among the nations, was believed on in the world, was taken up in glory.
The hymnic structure of the final phrases is evident. It represents one of a few well-attested examples of early NT liturgy or catechizing. It exemplifies what the church should always be doing: distilling the great truths of the gospel into crisp, beautiful, memorable sentences. The church at Ephesus had just this kind of responsibility to the truth, as we do today. This responsibility comes from what the church is—responsibility comes from identity. The church is the “pillar and foundation of the truth.” In context, these words refer not to the origin of the truth, but the proclamation of the truth. In other words he is not saying that truth gets its authority from the church. He is saying that it is the church’s responsibility to keep the truth above ground, up where everyone can see it. Included in this are both propagation and perpetuation.
What truth shall be propagated? The victory of Christ over sin and death is the central truth. This victory is exhibited in the worldwide reception of Christ by the nations and in the heavenwide reception of Christ by the angels. He is Lord with all authority. He reigns over the earth and heaven as God’s Man, the final Messiah, and the message of his victory spreads by means of assemblies of sinners who have experienced a taste of the kingdom life he will one day usher in.