One of the challenges in teaching theology is to help students to understand what they are learning as a comprehensive system, rather than a loose collection of unrelated facts. Christian theology has a center; it has rules of engagement; there is a proper order to its doctrines, and they fit into a certain hierarchy. 

A helpful exercise in driving this point home is to have students draft or identify a statement which sums up all Christian theology, and from which all the major doctrines of theology can be unpacked. Take, for example, Paul’s command in Romans 13: “Put on the Lord Jesus Christ.” How can this phrase be used to expound Christian doctrine? Consider this brief outline:

1. Theology. In the Old Testament, we are told that the Lord our God, the Lord is one. And yet Jesus, the One who worships the Father in the Spirit, is Lord. This one Lord, therefore, is Father, Son, and Holy Spirit.
2. Creation. Jesus Christ is “Lord,” because he is one with the divine essence; however, the context of his Lordship in Paul’s command is both creation and redemption. The world and all that is within it belongs to the Lord Jesus because it was made by the Lord Jesus. It is the stage upon which the drama of redemption is to be played out, and is, therefore, ingredient in God’s plan of redemption, not accidental to it. Creation is both signal and celebration of Jesus’ Lordship. It shows his power, wisdom, creativity, goodness, grace, and love as this One who is Lord. It is the sphere of redemption and reconciliation, the place wherein we are to “put on the Lord Jesus Christ.”
3. Sin. The context of the command is that we need to put on the Lord Jesus Christ, and, as Paul continues, to “make no provision for the flesh, to gratify its desires.” Why is Jesus the anointed Christ, the global fulfillment of Israel’s anointed priest, making atonement for the people, her anointed king, the one who leads the people in righteousness, and her anointed prophet, the one who calls attention to the people’s covenant-breaking and leads them to repentance before God? Because of the reality of sin’s penalty, power, and presence.
4. Salvation. The good news of the gospel is not that we need an anointed savior, but that God has provided such a savior in the person of his own Son. And so Paul commands us to put on the Lord Jesus Christ; he does not despair at the impossibility of doing so, but implicit in his directive is the reality that we who have trusted in Christ can put on Christ. How? Only because it is the Lord Jesus Christ with whom we have to do.
5. Church. Who does Paul instruct to put on the Lord Jesus Christ? He tells those who have been caught up in the redemptive purpose of God to put on the Lord Jesus, who is their Lord not only by virtue of being their Maker but by virtue of being their Christ, their anointed savior. By God’s saving action, we who trust in Christ are brought in. We are made new, and part of that newness is the creation within us of new desires (such as the desire to put on Christ) and new capacities (such as the ability to put on Christ). We are the society of those who belong to Jesus, and who are putting on Jesus.
6. Last things. Paul’s command in Romans is set in an eschatological context: “Besides this you know the time, that the hour has come for you to wake from sleep. For salvation is nearer to us now than when we first believed. The night is far gone; the day is at hand. So then let us cast off the works of darkness and put on the armor of light” (Romans 13.11–12). The command to put on the Lord Jesus Christ, assuming as it does a point of past salvation and being a directive toward present sanctification, plots for us two points on a timeline which is not circular, but linear. The drama of redemption nears its end. That end has us clothed in Christ, completely remade in a world which has been similarly transformed to be fit for this new humanity. “And so we shall be forever with the Lord.”

Theology as a human action is moving always toward center, toward Jesus and faithfulness in him. We should always be seeking therefore to be more faithful, more accurate, more consistent in our thinking about God and Christ, and our speaking about God and Christ. “Exercise thyself… unto godliness.”