Do I have to attend church every Sunday?
Simply put, can you be a true christian and not go to church? Or is it a mandate to go to church on Sundays?
Actually yes it is of course quite possible, but if someone is asking this question at all, it is likely that there is some other issue. Fellowship and the community of saints is such a basic part of the Christian faith that someone who wants to avoid that part on purpose has probably not understood the purpose of church at all and may not have the kind of regenerated heart that would want such a thing.
An interesting note on this issue is that it is usually those who for whatever reason cannot easily fellowship that understand it's value the most. Christians living in areas where they are persecuted for their faith believe so strongly in their need to meet together that they are often willing to risk their lives for it. It is primarily in affluent secular cultures were the desire to NOT attend creeps into circles of professing Christians. Anybody asking this question should be challenged to re-consider whether they know what being a Christian is all about in the first place.
One starting point is to review what scriptures say about the matter. A vast number of the instructions given to Christians for implementing their faith have to do with our treatment of one another, and the Lord's day is given lots of treatment in the Scriptures as well.
The Bible says, in Hebrews 10:25:
Believers are encouraged to fellowship as members of the Body of Christ. Without this, it is inevitable that one would grow cold in the faith. We need support and encouragement from fellow believers in order to grow in our faith.
The Christian faith is not about rules and laws. Hence, there is no law that says one has to go to church. We are at liberty to worship God in spirit and in truth (read John 4), but if we are truly walking with Him, then His Spirit living in us leads us to do His will. Thus, going to church is not a must, but the true Christian will naturally seek fellowship with other believers. For many, this involves becoming faithful members of a church. Christians are also called to serve the Body of Christ, and church is often a great place to start.
I will close by saying one can be a churchgoer and not a true Christian, while another can be a true Christian and not a churchgoer. There are many sold-out Christians in today's world who live in countries where public Christian worship is against the law, and they have to secretly meet in each other's homes. This is just one example.