This scripture does not say the Kingdom of God is in the hearts of men.
Jesus was talking to the Pharisees (verse 20). He called them hypocrites and blind fools
(Matt. 23:15-19). A number of them will never be in God’s
Kingdom (Luke 13:27-28). Christ was not saying the Kingdom of
God was in the hearts of those self-righteous, hypocritical Pharisees.
The Kingdom of God cannot be in the heart of any human being.
The scripture says flesh and blood cannot inherit the Kingdom
of God(I Cor. 15:50).
A kingdom has four parts: a king or ruler, subjects or
people, territory and laws. These cannot be in the heart of a person.
The Greek word translated “within” in verse 21 can also be
rendered “among” or “in the midst of.” The marginal
references of many Bibles show this as an alternate translation.
Jesus Christ was the representative of God’s Kingdom, and He was standing among them
or in the Midst of them.