Can you do an excursus on a blog? I don't know. Let's give it a try. I want to think a little bit more about this idea of surveying the "unseen" before we dive into Reveal. After all, don't externals count for something in Christianity?

Certainly. Jesus tells us that we know a tree by its fruit (Matt. 7:17-19). James says that faith without deeds is dead (James 2:26). And Paul commends the Thessalonians based on the "report" he had heard about them, how they had "turned to God from idols to serve the living and true God" (1 Thes. 1:9). I trust that that turning of the Thessalonians must have looked like something in order to yield a report. Maybe the visible changes of their "turning" could have been surveyed, quantified, even graphed in color.  (See also 3:6ff.)

Hopefully, we can all agree on this much: true faith, true hope, and true love effect change. They alter externals. You can see it. Paul says as much in the same passage of Thessalonians: "We continually remember before our God and Father your work produced by faith, your labor prompted by love, and your endurance inspired by hope in our Lord Jesus Christ" (1 Thes. 1:3).

Their faith worked. Their love labored. Their hope endured. Outwardly. Visibly. Maybe even statistically.

Paul is also clear in this passage about what produced their faith, hope, and love: "For we know, brothers loved by God, that he has chosen you, because our gospel came to you not simply with words, but also with power, with the Holy Spirit and with deep conviction. You know how we lived among you for your sake. You became imitators of us and of the Lord; in spite of severe suffering, you welcomed the message with the joy given by the Holy Spirit" (1 Thes. 1:4-6).

Did you catch that? Paul presumptuously says that he knows that God chose them. But how? He says that he knows God has chosen them because the message of the gospel was preached; because the message was accompanied by the Spirit; and because of the evidence that followed—conviction, imitation of Paul's life, welcome, and joy in spite of suffering.

In other words, Paul rejoices over what's happening in Thessalonica both because of the external outcomes (conviction, imitation, welcome, joy), yes, but also because he knows that these outcomes were produced by God's ordained means: the gospel was faithfully proclaimed and those words were accompanied by the Spirit.

He rejoiced, in short, because the Word and Spirit had had their intended effect—external fruit.

But there are two things we must remember at this point. First, external outcomes like "conviction," "imitation," even "joy" can be produced by other means, like false prophecy, legalism, entertainment, or philosophical persuasion. You can have something that looks like peace where there is no peace (see Jer. 6 and 8). Second, neither Paul nor any biblical author guarantees that the preaching of the Word will produce evident fruit. Think of Jesus' parable of the soils. Sometimes the word will go out and produce real fruit; but sometimes it will produce temporary fruit or even no fruit, as with the seed that falls among thorns, rocky soil, or on the path.

Let me draw all this into several conclusions: (i) Christian growth (and even the unseen quantities of faith, hope, and love) can sometimes be seen and maybe even measured.

(ii) Christian growth occurs through God-ordained means, namely, the Word and the Spirit.

(iii) Churches should therefore strive to ensure both that their methods are faithful to Scripture and that the externals of people's lives are broadly in keeping with their profession—that the seen is in keeping with the unseen. How else will you pick leaders, whose lives are to be above reproach? How else will you enact church discipline?

But there are four more conclusions I would add: (iv) Non-God ordained means (like false prophecy) can produce what looks like fruit—see Jeremiah 6 and 8.

(v) God ordained means (like preaching the gospel) can sometimes produce what looks like fruit but isn't—see parable of the soils. 

(vi) Therefore, churches should strive principally to be faithful to God's ordained methods of ministry (preaching, prayer, etc.), knowing he will produce visible fruit when and where he pleases, fruit for which we can rejoice.

(vii) To some extent, we are called to inspect that fruit, as with choosing our leaders or with disciplining the unrepentant. However, to adopt the methods that best yield visible fruit clearly puts the cart before the horse. It overlooks conclusions iv and v. More than that, it presumes the wisdom of man is greater than the wisdom of God. Instead, all our work, labor, and endurance must be accomplished in faith, in hope, and in love.