When you watch new construction on a building from the outside, everything that is going on under all the scaffolding and house wrap can seem like a mystery. Something is obviously taking shape, but for anyone other than the architect it can be difficult to fully imagine the end result.

In the unfolding drama of the Old Testament, the mystery of God’s will resembles scaffolding and wrap, shrouding certain parts of the biblical story until, as Paul puts it, “the fullness of time had come” (Galatians 4:4). Even as the prophets themselves prophesied concerning the one who was to come, they could only guess at the full meaning behind all the hints and clues laced throughout their writings (1 Peter 1:10-11).

In biblical language, a “mystery” isn’t a puzzle waiting to be solved by human ingenuity. Rather, it is a secret that is waiting to be revealed by God. Through the work of His Spirit in our hearts and minds, many of God’s mysteries become comprehensible to us. Apart from His work, we cannot understand them.

After His resurrection, when Jesus had the opportunity to address the unhappy travelers on the road to Emmaus, He responded to them in a loving yet strategic way (Luke 24:18-27). At first, they hadn’t recognized Him, asking, “Are you the only visitor to Jerusalem who does not know the things that have happened there in these days?” (How ironic!) Jesus simply responded, “What things?” He wanted to draw them out. Then, after they had shared the story of His crucifixion and resurrection, He said to them, “O foolish ones, and slow of heart to believe all that the prophets have spoken!” They hadn’t yet understood the mystery—and so, Luke tells us, the Lord clarified it: “‘Was it not necessary that the Christ should suffer these things and enter into his glory?’ And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself.”

“The mystery of his will” has been—indeed, is being—made known to God’s people so that He might “unite all things in him.” One day, when all the seasons which the Father has fixed by His own authority have run their course, all of this unity will come to fruition. Finally, the scaffolding, tarps, and wrapping will be stripped away, and we will see the building in its completion. Until that day, we can be grateful that the Lord has revealed the mystery of salvation to us, and we can walk in service and praise of Him, confident that while we may not understand the plans or the progress toward completion, the divine Architect is working out all things for the good of His people and the glory of His Son.