'Kingdom of God' in the Bible

Now, following His death on the cross [and resurrection], Jesus appeared alive [to His apostles] for forty days, and demonstrated by many convincing proofs [that He had been raised bodily from the dead]. [During that time] He also spoke to them about the [coming] kingdom of God.

Paul went into the Jewish synagogue and spoke boldly for three months, discussing and convincing people about matters regarding the kingdom of God.

And when they had arranged a day, large numbers of people came to Paul's house. He explained [everything to them], testifying from morning until evening concerning the kingdom of God and concerning [the Messiahship of] Jesus, both from the law of Moses and from [the writings of] the prophets.

He preached to them about the kingdom of God and taught things about the Lord Jesus Christ, with no one preventing him.