Church attendance is a discipline that benefits an individual relationship with God. We are either learners or teachers, and we are usually both at the same time. We must learn from one another, from other Christians. Every Christian should be able to teach the basics of the faith, to give an answer concerning our hope in Jesus Christ. They should pass truth along to new generations.
Much teaching is done by pastors.
But Paul commands every Christian to teach. Small groups provide one way to do this. Mature Christians can teach both in word and by example. When their faith is weak, they can seek the encouragement of others. When their faith is strong, they can help the weak.