The Beatitudes

One of the best known Gospel reading is Matthew 5:1-12a.  The passage from Matthew marks the opening of the Sermon on the Mount, the first of Jesus' sermons in Matthew. This part of the Sermon on the Mount is known as the Beatitudes.  A beatitude is an exclamation of congratulations that recognizes an existing state of happiness. See The New Jerome Biblical Commentary, p.620.

The importance of the Beatitudes cannot be overlooked. Bishop Fulton Sheen, in Life of Christ, takes the position that no one can truly understand the Mount of Calvery without understanding the Mount of the Beatitudes:

He who climbed the first to preach the Beatitudes must necessarily climb the second to practice what He preached. The unthinking often say the Sermon on the Mount constitutes the "essence of Christianity." But let any man put these Beatitudes into practice in his own life, and he too will draw down upon himself the wrath of the world. The Sermon on the Mount cannot be separated from His Crucifixion, any more than day can be separated from night. The day Our Lord taught the Beatitudes, He signed His own death warrant. The sound of nails and hammers digging through human flesh were the echoes thrown back from the mountainsides where He told men how to be happy or blessed. Everybody wants to be happy; but His ways were the very opposite of the ways of the world. (p.114)

The Catholic Encyclopedia entry on the Beatitudes echoes this that:

the eight conditions [the Beatitudes] required constitute the fundamental law of the kingdom, the very pith and marrow of Christian perfection. For its depth and breadth of thought, and its practical bearing on Christian life, the passage may be put on a level with the Decalogue in the Old, and the Lord's Prayer in the New Testament, and it surpassed both in its poetical beauty of structure.

There are two versions of the Beatitudes in the New Testament. The reading from Matthew is:

When Jesus saw the crowds, he went up the mountain, and after he had sat down, his disciples came to him. He began to teach them, saying:

“Blessed are the poor in spirit, for theirs is the Kingdom of heaven.
Blessed are they who mourn, for they will be comforted.
Blessed are the meek, for they will inherit the land.
Blessed are they who hunger and thirst for righteousness,
for they will be satisfied.
Blessed are the merciful,  for they will be shown mercy.
Blessed are the clean of heart, for they will see God.
Blessed are the peacemakers, for they will be called children of God.
Blessed are they who are persecuted for the sake of righteousness, for theirs is the Kingdom of heaven.
Blessed are you when they insult you and persecute you
and utter every kind of evil against you falsely because of me.
Rejoice and be glad, for your reward will be great in heaven.”

The Beatitudes are also shown in Luke (6:22-26), although there is a reduction number of "blessings" and the contrast of what are known as the "four woes":

And raising his eyes toward his disciples he said:
"Blessed are you who are poor, for the kingdom of God is yours.
Blessed are you who are now hungry, for you will be satisfied. Blessed are you who are now weeping, for you will laugh.
Blessed are you when people hate you, and when they exclude and insult you, and denounce your name as evil on account of the Son of Man.Rejoice and leap for joy on that day! Behold, your reward will be great in heaven. For their ancestors treated the prophets in the same way.
But woe to you who are rich, for you have received your consolation.
But woe to you who are filled now, for you will be hungry.
Woe to you who laugh now, for you will grieve and weep.
Woe to you when all speak well of you, for their ancestors treated the false prophets in this way.

Many people have difficulty in understanding the first beatitude: Blessed are the poor in spirit, for theirs is the Kingdom of heaven. What exactly does that mean, to be poor in spirit?

As noted in the readings set forth above, the words in spirit are found in Matthew's version but not Luke's. The New Jerome Biblical Commentary make the following observation on this addition:

Matthew's editorial additions may be seen in several places. First he adds "justice" in vv 6 and 10, both as a formal divider and as one of the great themes of his Gospel. To "blessed are the poor" he adds "in spirit." The poor are the needy ones of Israel, ... who prefer the divine service to financial advantage. Their poverty is real and economic, but with a spiritual dimension. In Matt the addition of "in spirit" changes the emphasis from social-economic to personal-moral: humility, detachment from wealth, voluntary poverty. In the Bible economic destitution is an evil to be corrected (Deut 15:11), and wealth is not an evil in itself; indeed, it is a necessity for the well-being of the kingdom, but it risks neglect of God and of the poor. God's first priority is the care of the poor.

The other beatitude which often causes confusion is the second one,  Blessed are the meek, for they will inherit the land.  Confusion here arises because few people take the time to look up the meaning of the word "meek" and operate under the presumption that it means being a shy or reserved person. Instead, "meek" means to endure injury with patience and without resentment.