Just going to church doesn't make us a Christian. We're saved by grace through faith because of Jesus' life, death, and Resurrection. So, a believer will not lose his or her salvation if they don't go to church.
However scriptures teach us that the Christian life should be lived within the family of God and not in isolation. Ephesians 3: 4-15 Acts 2: 42-47. Hebrews 10: 24-25 and let us consider how we may spur one another on toward love and good deeds, not giving up meeting together, as some are in the habit of doing, but encouraging one another... When you become a Christian, you were called into a relationship with God 1 Corinthians: 1-9, but, 1 John:1-3 makes it clear that we enter a fellowship that goes two ways: with God and with other Christians.
Acts 20:7 reveals the practice of the early church the first day of the week the disciples came together to break bread and Paul preached to them. For Christians in every location regular Gathering was a part of life.
Unity of the body of Christ- now you are the body of Christ, and each one of you is a part of it 1 Corinthians 12:27. It's not logical to say that you are just a part of the worldwide church yet refused to gather with the part of that church that exists in your area. Dr. John Bechtle says, "it would be like claiming you have a car, when the right fender is in Phoenix, the engine is in Tucson, and the wheels are in Paradise Valley! You don't have a car; you have the beginning of the inventory for a junkyard. It just won't function until all the pieces are put together." There are many irreplaceable pieces of a Christian that cannot exist when she/he lives in isolation from the church.
Accountability- God designed the church as a place where spiritual leaders could watch out for our welfare. 1 Peter 5:1-4, Hebrews 13:17. A Christian who answers only to himself can easily rationalize sinful attitudes or actions; regular contact with other Christians can keep us Sharp.
Use of spiritual gifts- 1 Corinthians 12 makes it clear that God has given spiritual gifts to every Christian. Verse seven states that these abilities are not provided just to make us feel good they are abilities to minister that should be used for the common good. 1 Peter 4:10 commands us to use the spiritual gifts to help each other. We will discover a sense of accomplishment and contentedness when we begin to carry out our purpose in the body of Christ. We are the ones who miss out on all the blessings of God and the gifts of our "family members" if we choose not to be a part of Christ's body. We meet with other Christians so they can use their gifts to strengthen us. God's Gift of a minister is wasted if no one comes to hear them speak.
Mutual Ministry- God intends each of us to meet the needs of other believers, using our strengths to help and their areas of weakness. Dr. John Bechtle relates, that
"The New Testament is full of 'one another' commands. We are to comfort one another (1Thessalonians 4:18), build up one another (1Thessalonians 5:11), confess our sins to one another snd pray for one another (James 5:16) and many more. How can we obey these directives if we stay away from the Gathering of believers?"
Developing the character of Christ- Ephesians 4:2 be completely humble and gentle; be patient, bearing with one another in love. How else will we grow spiritually unless we interact with other believers? We learn humility, patience, and gentleness as we interact with one another in the body of Christ.
Spiritual Protection- 1 Peter 5: 1-4
Our leaders in the body of Christ keep watch over us for our own protection and blessing. There will be difficult moments as part of a church family but there are also blessings that we will never experience unless we become connected to the body of Christ.