This section of 1 Timothy is the center of the letter, perhaps the center of the three Pastoral Epistles as a whole. The main metaphor Paul works in this letter is the Household of God. Timothy is a pillar in that household and responsible for the spiritual life of other members of the household. Some people in Ephesus have rejected key doctrines of the faith and have developed some behaviors which are not scriptural. In order to argue against these opponents, Paul first describes what he calls the “mystery of godliness” before turning to some examples of the un-truth which the opponents are teaching.
Paul’s concern in 1 Timothy is that the churches in Ephesus see themselves as part of the “household of God.” If one is a member of a particular household, they must behave according to that household’s rule. Members of a Roman household had very clear roles and expectations. Fathers, children, and servants all had clearly defined roles in Roman society and it was honorable to do what was expected of you as a father, child, servant, etc.
In fact, it would bring shame upon a household if a father did not perform his role as leader of the family properly, or a child behaved in a way so as to dishonor on the family name. As an analogy, think of a powerful political family in America. Since the family name is well known, there are some things which a family member cannot do without bringing some kind of shame or scandal to the family, endangering their political aspirations. Paul has taught throughout this letter that people within the church are part of a new household, God is their father and they have a role to play within the order of the household of God.
Paul describes the Church as a “pillar” in that household, and a “buttress of the truth.” The metaphor shifts from a household to a Temple, with a foundation and pillars. Both of these metaphors refer to a building. Paul called Peter and James “pillars of the church” in Galatians 2, indicating that they were the chief leaders. Here Timothy is the “pillar” and main support for the churches at Ephesus. A buttress or bulwark (ἑδραίωμα) is like a foundation, the verb is used for founding something on a good foundation.
While the church is like a pillar in the household of God, the church itself is built on the truth (v. 15). This is not unlike Eph 2:19-22, the church grows into a holy temple for God, built on the prophets and apostles (pillars?) and built on the foundation of Jesus Christ.
In both cases the point of the metaphor is that the Church stands on the foundation of truth, that it is to guard and defend the truth of the Gospel against defections from the truth. This looks back to how Paul started the letter; in 1:3-7 he warned Timothy about people who were swerving from the truth, both in doctrine and practice.
True godliness begins with Jesus and his work on the Cross (3:16) Paul describes the godliness expected by a member of the household of God as a “great mystery.” He uses the word “confess” (ὁμολογουμένως) perhaps indicating that this short description of the work of Jesus was used as a public confession or doctrinal statement in the early church. The word has the sense of agreement, “this is something that we all agree on.”
This mystery of godliness is called “great.” While it is hard to know if Paul had this in mind, the riot in Ephesus in Acts 19 culminated in the Ephesian crowds chanting “great is Artemis” for hours. Rather than a great god like Artemis, Paul proclaims a living God, rather than a great temple like the temple of Artemis, Paul declares that the church itself is the household of God.
How is this a mystery? The word (μυστήριον)often refers to God’s revelation of something which could not be known unless it was revealed by God. It is the secret which the church guards, how to be “godly.”