We live in a day and age where the institutional church is thought of as unnecessary. In Reformed circles, the thought that the visible church is unnecessary would never be spoken in words. Instead it would be spoken in actions. How often do you attend church? What kind of excuses do you think are acceptable to not be in church? Answers to these questions reveal, among reformed people, an attitude that the church is really not that important.
So why is the church important? Unfortunately we have to actually answer this question today. But I can think of no better answer than that of the Westminster Confession chapter 25 article 3. It says, "Unto this catholic visible church Christ hath given the ministry, oracles, and ordinances of God, for the gathering and perfecting of the saints, in this life, to the end of the world: and doth, by his own presence and Spirit, according to this promise, make them effectual."
Church is important because it is the only place where you could find God working through the ministry, oracles and ordinances of God. These are not at the mall on Sunday, nor at home in bed, nor anywhere else. The reason why these are important is because God uses them for the gathering and perfecting of the saints. In other words, our spiritual growth will be hindered or it will flourish depending upon how regularly we make use of the ministry, oracles and ordinances of God.
This means that pastors must encourage members to regularly go to church. This means that fathers must be the spiritual head and make sure that their families come to church regularly. This means that we as individual Christians must take responsibility for our own spiritual welfare and come to church regularly. To not do so is like refusing food to the physical body. The less food our bodies receive the more unhealthy the body will be and it will wither away.
So the lesson here is that we cannot think of the church as unnecessary. Nor can we think of the church as something we will come to if our circumstances make it convenient. Instead, we ought to make every effort to be in church because this shows us where our real priorities lie.