Mutual edification is the primary reason for the gathering of the church. Although various activities may occur as the body comes together, the goal of the assembling is that the church family be built up together.
The priesthood of all believers describes what the church is. The moment a person surrenders to Christ in faith, he also becomes a priest to God. The challenge is living out this priesthood.
As we think about these two things (mutual edification and the priesthood of all believers), we see a link between the two. The priesthood, in fact, helps us define what mutual edification actually is.
What is mutual edification? Here's my definition: Mutual edification is helping each other live more effectively as the priests we already are.
We don't try to help other believers become priests. That would be like trying to help believers get saved. All believers are positionally priests. God makes it happen.
The challenge and great privilege for all of us is actually taking responsibility to live out being the priests we are. As the body gathers, we encourage and exhort one another in ways that assist all present in both growing closer to Christ and becoming more like Him.
Paul, among others, addresses these issues in familiar passages. In Romans 12:1 the apostle appeals for the church in Rome to live as the priests they are, saying, "I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship." How do the believers get to the point of doing this? One way is through mutual growth. I Corinthians 14:26 tells us, "What then, brothers? When you come together, each one has a hymn, a lesson, a revelation, a tongue, or an interpretation. Let all things be done for building up." When the church congregates, everything is for edification.
It's a wise thing to give thought to how we will edify others when we come together. This does not mean that we plan it all out, but rather that we just be prepared. In order to do this, it's good to know what the goal is. One good way to think about the goal is that it's helping priests live more priestly.