Well, I guess one could ask necessary for what?
Is attending church necessary to enter heaven? No. Is attending church necessary for a full Christian life? Probably. Does God expect Christians to attend church? Yes. The writer of Hebrews under the inspiration of God’s Holy Spirit commands Christians “to consider one another in order to stir up love and good works, not forsaking the assembling of ourselves together, as is the manner of some, but exhorting one another,”
Luke, in the Book of Acts, describes how after Peter preached, 3,000 received the word of God, were baptized, and “continued steadfastly in the apostles’ doctrine and fellowship,” and met “daily with one accord in the temple.” Luke further along says, “And the Lord added to the church daily those who were being saved.”
What Christians call fellowship is an important part of a Christian’s life. And much of that fellowship occurs in church.
A gathering of Christians is where we are encouraged and inspired. Paul tells Christians in Ephesians that they are “created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.” Church is an excellent place to be involved in good works.
Paul, in First Corinthians, tells us that the Christian church is one body made up of many members. He compares that body to our human body saying that all members of the body of Christ are necessary because God has set them in the body just as He pleased.
Those who say they can have a relationship with God without gathering together fail to benefit from the love and caring of other Christians or offer the same. Unavailable also is receiving or giving Biblical instruction and godly counsel.
John, in his first epistle, admonishes Christians to love one another. That’s hard to do if we’re absent from church.