Matthew 5:1 ->12
Blessed are the poor in spirit, for theirs is the Kingdom of Heaven.==================================================
Blessed are those who mourn, for they shall be comforted.
Blessed are the meek, for they shall inherit the Earth.
Blessed are those who hunger and thirst for righteousness, for they shall be satisfied.
Blessed are the merciful, for they shall obtain mercy.
Blessed are the pure in heart, for they shall see God.
Blessed are the peacemakers, for they shall be called children of God.
Blessed are those who are persecuted for righteousness sake, for theirs is the Kingdom of Heaven.
Blessed are you when men revile you and persecute you and utter all kinds of evil falsely on my account. Rejoice and be glad, for your reward from Heaven is great; so men persecuted the prophets who were before you.
For such a popular passage, I've always found this difficult. "Blessed are the poor in spirit?" That's redundant, with "Blessed are the meek." Luke has this as "Blessed are the poor," which adds something significant, and is likely the original quote -- except that I haven't observed poor people in general to be anything but wretched & harassed.
First off, Jesus is talking about how things are to be within God's kingdom, that is, for those enjoying the active participation of God in the world around them. Most people, no matter how good, have not been able to experience this, but remain solidly planted in that other guy's realm. So far as we want to be good, we are in fact responding to God's influence; but so far as people haven't been generally willing to let God actually rule their lives, the results have been uneven.
There is, of course, the traditional image of a 'king' as the man who sits on a throne and orders people about. He is supposed to take requests from his subjects; but which requests are granted will be based on his personal decision. Abraham breaks that mold; so does Moses. These paradigms of good relationships with God -- frequently dicker with Him like oriental merchants.
Rather than seeing God as our King -- we can better see the relationship as one of students to their teacher, or as Jesus had it, as children to their parent. But the power disparity is absolute; and so is the gap in wisdom between us; hence God will call the shots, and it makes a lot of sense for us to welcome that. We simply don't. God has too much power for our comfort; God's wisdom goes deeper than ours and is likely to surprise us with difficult learning-situations. People compulsively insist on telling God how to rule; and it shouldn't surprise us that this hasn't worked.
God's realm is called 'a kingdom', I would say, because God was considered Israel's King from the time this people were freed from slavery until they demanded a human monarch. When a popular leader like Gideon was invited to be king, he would say: "I will not rule over you; and my sons will not rule over you; but the Lord will rule over you." Leaders who departed from that pattern soon made themselves intensely, deservedly unpopular; and when Saul, then David, became kings, they also misbehaved and suffered no end of revolts.
This is what the 'Kingdom of God' would mean to Israel in ancient times, and to Jesus' followers -- not another human king to take the crops and enslave one's children, but the active rule which God had exercised in freeing their ancestors, as their national story insisted.
Those who could benefit most from accepting God's jurisdiction would be the poor, those who were suffering or timid, people who wanted to promote and receive justice and mercy, those who insisted on truth rather than popular falsehoods.