That's the Kingdom of God

Matthew 10:7-8 – “Go and announce that the kingdom of heaven is near. Heal the sick, raise the dead, cure those with leprosy, and cast out demons. Give as freely as you have received.”

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One thing that I don’t do is announce that the kingdom of heaven is near. Is this something that we are still required to do? The only people we see doing this today are the homeless with their cardboard signs, and that is usually in movies. The homeless don’t seem to have the spirituality that they used to. But my question is what is the kingdom of heaven, and what is our responsibility to it? What should we be declaring to others. It is bad that I don’t know this? Anyone have any ideas on what the Kingdom of heaven is and what our responsibility is to it today?