But if I tarry long. — St. Paul felt that dangers were pressing closer and closer — that the hoped-for visit to his loved church at Ephesus might not, probably never would be, accomplished; so these foregoing solemn directions respecting the choice of colleagues in the ministry had been written to Timothy, that, in the event of St. Paul never coming to him again, men (especially the ministers of God) should know how to conduct themselves in the congregation.
That thou mayest know how thou oughtest to behave thyself. — The words refer here not to Timothy alone, but rather to Timothy and his colleagues in their church work, concerning whom such particular directions had just been given, and should be rendered, how men ought to behave themselves.
In the house of God. — The image is from the Old Testament, where “the house of God” denotes, in the first place, the Temple of Jerusalem, and, in the second, the covenant-people. It is here used for the congregation of believers among whom God dwells — the true and enduring Church of living souls. Of this great spiritual temple, the corner-stone of which is Christ, the Jerusalem house on Mount Zion, with its marvellous work and its gorgeous and elaborate symbolism, was the poor, perishable, hand-wrought model.
Which is the church of the living God. — The house of God is here plainly defined to be the “Church” (or, congregation) “of the living God,” who was working in its midst actively and personally, in strong contrast to that well-known graven image of the Diana of Ephesus, throned in that fair temple which glittered in its white and lifeless beauty over the roofs of the city where Timothy’s charge lay.
The pillar and ground of the truth. — The imagery is here changed, and the “house of God” which the Apostle had just defined to be the Church, or congregation, belonging to the living God, and in the midst of which He was pleased to dwell, is now defined to be “the pillar and ground” (or, basis) “of the truth.” In the first picture, the Church is painted by St. Paul as a vast congregation, with the living God dwelling in its midst: in the second, the same Church is painted as a massive pillar, holding up and displaying before men and angels the truth — the saving truth of the gospel. In the first picture, the thought of a great company gathered together for God to dwell among is prominent: in the second, the thought of the great redemption-truth alone comes to the front, and the Church of God is no longer viewed as a company of separate individuals, but as one massive foundation-pillar, supporting and displaying the glories of redemption.
This peculiar aspect of the Church, ”the support and pillar of the truth,” was dwelt upon probably by the Apostle as “defining — with indirect allusion to nascent and developing heresies — the true note, office, and vocation of the Church.... Were there no Church, there would be no witness, no guardian of archives, no basis, nothing whereon acknowledged truth could rest” (Ellicott).