As a child, I was aware that, at night, infrared vision would reveal monsters hiding in the bedroom closet only if they were warm-blooded. But everybody knows that your average bedroom monster is reptilian and cold-blooded.
Some Christians try to go to heaven alone, in solitude; but believers are not compared to bears, or lions, or other animals that wander alone; but those who belong to Christ are sheep in this respect, that they love to get together. Sheep go in flocks, and so do God’s people.