…but we preach Christ crucified, to the Jews a stumbling block and to the Greeks foolishness, but to those who are called, both Jews and Greeks, Christ the power of God and the wisdom of God. (1Co 1:23-24 NKJ)
83. What is the Office of the Keys?
The preaching of the Holy Gospel and Christian discipline; by these two the kingdom of heaven is opened to believers and shut against unbelievers.
Heidelberg Catechism question 83-84 shows us how it is that the right preaching of the Word (along with Christian discipline) makes clear the way into the kingdom of heaven. When it says that the church opens and shuts the gates, it is of course not saying that the church can make people elect or not elect, saved or not saved. That belongs to God alone. When Jesus says that whatever the church binds on earth shall have been bound in heaven (Matthew 16:19; 18:18) He is saying that when the church does its job properly then the actions of the church reflect heavenly realities- when the church properly declares someone outside the kingdom of heaven, that reflects the truth of that person’s standing with God. That assumes that the church acts according to the truth of Scriptures.
When the church preaches the Word of God, the church declares the truth delivered to us by Christ — that salvation and rescue from sin and death is to be had by repentance and faith in Jesus Christ and in no other way. By this action, the gates of the kingdom of heaven are opened and shut- opened to those who receive the message and by faith in the word of God are then made part of that kingdom, and shut to those who obstinately refuse to hear God’s word.
Both of these aspects of the church’s work need to be kept in mind, by the leadership of the church and by its members. The passage from 1 Corinthians 1 quoted above shows that there will be people of all backgrounds (Jews and Greeks- an all-inclusive concept to Christians of those days) who cannot fit Jesus into their worldview. The right preaching of the gospel shuts the doors against them.
But there will also be people from all backgrounds who have this in common- they are called of God and therefore they hear the truth of the Gospel, they see the kingdom of God and they enter in. The church is not a social club full of people who are comfortable with each other’s educational backgrounds, economic status or ethnicity, but people from every tribe and kindred who have been called by God to hear the gospel.
We dare not try to open or shut the gates of the kingdom ourselves. We do not decide who is and is not a worthy member. It is God’s word, and He decides who rightly belongs in the kingdom, and the faithful preaching of the Word is one of His chief means to do so.