To me, we are ALL a part of the Kingdom of God.
We were all born in sin. We all need salvation. This is why Jesus died on the Cross and why we need to humbly come to Him to have the Blood applied.
John
3:3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
3:4 Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and [of] the Spirit, he cannot enter into the kingdom of God.
3:6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
3:7 Marvel not that I said unto thee, Ye must be born again.