Christ says His words are Spirit and Life; they have a quality above human words because their source is divine. If ingested, these words lead to eternal life.
The 'kingdom of heaven' is commonly interpreted to describe the church, but in the first four parables of Matthew 13, it has a clearer application: Israel.
We should not expect brethren to be perfect; we all sin. God has not given His People the prerogative to judge another member as a tare.