The Bible stresses the importance of going to church. However it must be remembered that a person becomes a member of the true church the moment they believe in Jesus. The church is made up of every true believer in Jesus, it is not necessarily the same people who walk into a church building every Sunday morning.
Having said that, it is important for believers to assemble with other believers. There are several reasons why this is the case:
Commanded By God
First, we should go to church because it is commanded by God.
Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another - and all the more as you see the Day approaching (Hebrews 10:25).
Since God commands us to meet with fellow believers, we do so to be obedient to His commands.
Fellowship
One of the reasons for going to church is having fellowship with other believers.
Who comforts us in all our tribulation, that we may be able to comfort those who are in any trouble, with the comfort which we ourselves are comforted by God (2 Corinthians 1:4).
We are able to comfort one another with God's comfort. Together we can share our victories as well as our defeats. The church should be a place where people can be loved and accepted unconditionally, just as Christ has accepted us just as we are.
Teaching
Going to church is also important for the purpose of receiving teaching. We grow in our Christian experience as we are taught God's Word and we learn more about who God is, who we are, and what His plan for us consists of. This can only be accomplished through a serious study of the Word of God.
Scripture commands us to give diligence to His Word.
Do your best to present yourself to God as one approved by him, a worker who has no need to be ashamed, rightly explaining the word of truth (2 Timothy 2:15).
Worship
We are created to worship and serve God. When believers meet together this can be accomplished. Worship is one of the ways in which we express our love toward Him. The Bible says:
Praise the LORD! How good it is to sing praises to our God; for He is gracious, and a song of praise is fitting (Psalm 147:1).
Summary
Though believers are the true church, it is important for those who have trusted Jesus to assemble together. We do this to encourage one another, and for the purpose of receiving teaching and worship. Assembling ourselves together is also something that is commanded by God.