To answer your question,

Jesus said, we are to worship God in Spirit and Truth!

One's spirit is dead, seperated from God before becoming a christian.

Those without the enlightenment of the Holy Spirit can not have full truth.

God is Love is true, But God is a jealous God too, he is also Just and requires repentance of us.

no matter how good one thinks they are apart from the true God, they just are not going make it.

Some say there is truth in all religions, my dad had an illustration that I think is fitting here. If your water was off for repairs and you filled your bathtub ( after cleaning it ) for drinking water. And, you start drawing water out of that tub while seeing someone at the same time or just before go to the bathroom in the other side of that same tub, would you drink that water?