1 Corinthians 3:12-15
With the foundation laid, we learn about the proper materials to use to build upon it:
“If anyone builds on this foundation with gold, silver, precious stones, wood, hay, or straw, the work of each will come to light, for the Day will disclose it. It will be revealed with fire, and the fire (itself) will test the quality of each one’s work. If the work stands that someone built upon the foundation, that person will receive a wage. But if someone’s work is burned up, that one will suffer loss; the person will be saved, but only as through fire.” -1 Corinthians 3:12-15, NAB
As we build the Church, we do so in our own lives. When we build upon the foundation that Saints Peter and Paul began, we must carefully choose the materials that we use to build it. Some will invest everything they have, using precious metals and stones. Others will not invest as much, only using the basic materials this world has to offer. But in this verse, Paul is not talking about the actual physical materials that we build the Church with, or even the money we invest, he is talking about the spiritual investment that we make. If we simply invest the bare minimums into our spiritual life, then we will only see the fruits that the bare minimum can bring. In other words, attending Mass twice a year is not living a fully-invested spiritual life. The same is true if we never step out of the pew to bring our faith out into the world. To build upon that foundation with precious metals and stones, we must make greater investments spiritually, including attending Mass regularly, partaking of the Sacraments, and living our faith outside of the four walls of the church. One day, our investment will be tried by fire, and someone who did not invest into their spiritual life will face struggles. The lack of spiritual strength will make them falter through those trials of life. With a strong investment in our spiritual life, through the grace of God, we can stand up to those trials, and at the same time, we can show the glory of God within us.