But if I tarry long, that thou mayest know how thou oughtest to behave thyself in the {7} house of God, which is the church of the living God, the {i} pillar and ground of the truth.

(7) The pastor always has to consider how he carries out his duties in the house of the living God, in which the treasure of the truth is kept.

(i) That is, with regard to man: for the Church rested upon that cornerstone, Christ, and is the preserver of the truth, but not the mother.

People's New Testament

3:15 But if I tarry. In that case he wrote that Timothy might understand how to act.

How thou oughtest to behave thyself in the house of God. Conduct thyself in the management of the church.

Which is the church of the living God. The house of God is not the temple of Diana, which stood there at Ephesus.

The pillar and ground of the truth. The church is the pillar and support of the truth because it preaches it to the world, preserves it, and transmits it from generation to generation.

Wesley's Notes

3:15 That thou mayest know how to behave - This is the scope of the epistle. In the house of God - Who is the master of the family. Which is - As if he had said, By the house of God, I mean the church.

King James Translators' Notes

ground: or, stay

Scofield Reference Notes

[1] church

Church (visible), Summary: The passages under this head 1Cor 10:32 1Tim 3:15 refer to that visible body of professed believers called, collectively, "the Church," of which history takes account as such, though it exists under many names and divisions based upon differences in doctrine or in government. Within, for the most part, this historical "Church" has existed the true Church, "which is his body, the fulness of him that filleth all in all Eph 1:22,23.

See Scofield Note: "Heb 12:23" like the believing Remnant within Israel

See Scofield Note: "Rom 11.5" The predicted future of the visible Church is apostasy Lk 18:8 2Tim 3:1-8 of the true Church, glory Mt 13:36-43 Rom 8:18-23 1Th 4:14-17.

Jamieson-Fausset-Brown Bible Commentary

15. But if I tarry long-before coming to thee.

that-that is, I write (1Ti 3:14) "that thou mayest know," &c.

behave thyself-in directing the Church at Ephesus (1Ti 4:11).

the house of God-the Church (Heb 3:2, 5, 6; 10:21; 1Pe 4:17; 1Co 3:16, "the temple of God"; Eph 2:22).

which is-that is, inasmuch as it is.

the church-"the congregation." The fact that the sphere of thy functions is "the congregation of the living God" (who is the ever living Master of the house, 2Ti 2:19, 20, 21), is the strongest motive to faithfulness in this behavior as president of a department of the house." The living God forms a striking contrast to the lifeless idol, Diana of Ephesus (1Th 1:9). He is the fountain of "truth," and the foundation of our "trust" (1Ti 4:10). Labor directed to a particular Church is service to the one great house of God, of which each particular Church is a part, and each Christian a lively stone (1Pe 2:5).

the pillar and ground of the truth-evidently predicated of the Church, not of "the mystery of godliness" (an interpretation not started till the sixteenth century; so Bengel); for after two weighty predicates, "pillar and ground," and these substantives, the third, a much weaker one, and that an adjective, "confessedly," or "without controversy great," would not come. "Pillar" is so used metaphorically of the three apostles on whom principally the Jewish Christian Church depended (Ga 2:9; compare Re 3:12). The Church is "the pillar of the truth," as the continued existence (historically) of the truth rests on it; for it supports and preserves the word of truth. He who is of the truth belongs by the very fact to the Church. Christ is the alone ground of the truth in the highest sense (1Co 3:11). The apostles are foundations in a secondary sense (Eph 2:20; Re 21:14). The Church rests on the truth as it is in Christ; not the truth on the Church. But the truth as it is in itself is to be distinguished from the truth as it is acknowledged in the world. In the former sense it needs no pillar, but supports itself; in the latter sense, it needs the Church as its pillar, that is, its supporter and preserver [Baumgarten]. The importance of Timothy's commission is set forth by reminding him of the excellence of "the house" in which he serves; and this in opposition to the coming heresies which Paul presciently forewarns him of immediately after (1Ti 4:1). The Church is to be the stay of the truth and its conserver for the world, and God's instrument for securing its continuance on earth, in opposition to those heresies (Mt 16:18; 28:20). The apostle does not recognize a Church which has not the truth, or has it only in part. Rome falsely claims the promise for herself. But it is not historical descent that constitutes a Church, but this only, to those heresies (Mt 16:18; 28:20). The apostle does not recognize a Church which has not the intermediate; the "ground," or "basement" (similar to "foundation," 2Ti 2:19), the final support of the building [Alford]. It is no objection that, having called the Church before "the house of God," he now calls it the "pillar"; for the literal word "Church" immediately precedes the new metaphors: so the Church, or congregation of believers, which before was regarded as the habitation of God, is now, from a different point of view, regarded as the pillar upholding the truth.

Matthew Henry's Concise Commentary

3:14-16 The church is the house of God; he dwells there. The church holds forth the Scripture and the doctrine of Christ, as a pillar holds forth a proclamation. When a church ceases to be the pillar and ground of truth, we may and ought to forsake her; for our regard to truth should be first and greatest. The mystery of godliness is Christ. He is God, who was made flesh, and was manifest in the flesh. God was pleased to manifest himself to man, by his own Son taking the nature of man. Though reproached as a sinner, and put to death as a malefactor, Christ was raised again by the Spirit, and so was justified from all the false charges with which he was loaded. Angels ministered to him, for he is the Lord of angels. The Gentiles welcomed the gospel which the Jews rejected. Let us remember that God was manifest in the flesh, to take away our sins, to redeem us from all iniquity, and to purify unto himself a peculiar people, zealous of good works. These doctrines must be shown forth by the fruits of the Spirit in our lives.