Paul was in Ephesus for three months, boldly proclaiming the kingdom of God in the synagogue.  He used reasoning and persuasive words.  (Acts 19:8)

Who can be in the kingdom of God?  Anyone can be a citizen in the kingdom of God by placing themselves in total submission to God and to His Christ (the Lord Jesus).
How can anyone do that?  Believing God’s words about the Lord Jesus and receiving Him as Savior.

Jesus said:
(NASB) John 3:3 “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.”

Everyone is physically born of the union of a man and a woman.
All believers are spiritually born of God through faith in Jesus and given God the Holy Spirit.  That is being born from above, that is being born again.

What choices does anyone have?  We live in darkness but we can live in the light of God.
(NASB) Colossians 1:13-14 “For He (God) rescued us from the dominion of darkness, and transferred us to the kingdom of His beloved Son,
14 in whom we have redemption, the forgiveness of sins.”

What does the Lord Jesus do for me?
(NASB) 2 Timothy 4:18 “The Lord will rescue me from every evil deed, and will bring me safely to His heavenly kingdom; to Him be the glory forever and ever. Amen.”

What is your response to such a salvation through faith in the Lord Jesus?
Only you can answer that.
There is excitement and purpose for those who are in the kingdom of God through faith in Jesus.

How can we learn and grow in our faith?  By studying God’s word and knowing it is true.  Knowing God is to believe His words which are all true.  For God does not lie, indeed, He cannot lie.

Are you a citizen in the kingdom of God?