We live in a day when Christians think that we are being unkind when we want to keep our worship pure and undefiled by the world by keeping ourselves separated from the world when we worship our God.
2 Corinthians 6:16-18 "…16 What agreement can exist between the temple of God and idols? For we are the temple of the living God. As God has said: “I will dwell with them and walk among them, and I will be their God, and they will be My people.” 17 “Therefore come out from among them and be separate, says the Lord. Touch no unclean thing, and I will receive you.” 18 And: “I will be a Father to you, and you will be My sons and daughters, says the Lord Almighty.”…"
Here is the passage where God speaks about this matter of including unbelievers in the worship of God. When we worship with believers we are yoked and in agreement in our worship and purpose. Non-believers cannot be in agreement. To include unbelievers is hypocrisy on their part because they don't love Christ, and unholy alliances on our part.
God told us to go into the world and make converts then bring them in as saved brothers and sisters. He never told us to go into the world and bring non-believers to the worship of our God.
2 Corinthians 6:14
"14 Do not be mismatched with unbelievers; for what do righteousness and lawlessness share together, or what does light have in common with darkness?"