There is really one primary passage in the New Testament on the importance of gathering together.
Hebrews 10:25 - Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.
I find it interesting that this is really the only command in the New Testament, as far as I have seen, that commands believers to come together. However, there are a myriad of exhortations about how believers are to interact when they are together. Don’t miss this. Believers gathering together did not have to be commanded repeatedly because it was assumed that that is what believers do.
God’s people are a gathering people. They have to come together. They long to come together. It is not the normal state of the Christian to live in isolation from other believers, but in community with other believers. However, we live in a time that isolation Christianity has become the norm. Many believers are content to watch their favorite preacher from home or join in on the livestream of the church, instead of having meaningful interactions with their brothers and sisters in Christ.
Link to episode on Christian Fellowship: