Jesus said He had come not to destroy but to fulfill (Matthew 5:17). It is chiefly in Matthew chapters 5-7, the Sermon on the Mount, that He does this.

1. The Beatitudes: In these Jesus reverses many of the currently held opinions, and promises happiness even here to those who would have been thought not very fortunate at best.

The First Beatitude: "Blessed are the poor in spirit, for theirs is the Kingdom of Heaven."

Poverty was often thought of as merely misfortune. Jesus does not call mere physical poverty blessed. He speaks of a poverty in spirit, that is, in detachment from the things of this world, so one does not allow them to get a hold with their pulls.

The Second Beatitude: "Blessed are the meek, for they shall inherit the land"

The meek are those who are unassuming, considerate, and far from the spirit of revenge, which desires evil to another so it may be evil to him: the very opposite of love. The land in God's ancient promises meant the land of Israel; it had been reinterpreted by this time to mean Heaven. Even in this life, meekness often brings returns.

The Third Beatitude: "Blessed are those who mourn, for they shall be comforted".

Jesus opens a new perspective on sorrow and pain: if accepted as part of following after Him, it is not only not a punishment for sin, as many Jews thought (cf. John 9:2), but a means of greater likeness to Christ, and brings even here divine consolation, of which St. Paul spoke in 2 Corinthians 2:4-5.

The Fourth Beatitude: "Happy are those who hunger and thirst for the right; they will get their fill."

God's supreme Holiness loves everything that is right; in this beatitude a soul imitates Him in this. Hence Matthew 6:33 adds: "Seek first the Kingdom of God and the rightness He loves, and all these things will be added to you."

The Fifth Beatitude: "Happy are the merciful; they will have mercy shown to them."

The merciful here mean those who help in all sorts of need, and forgive those who offend against them. God who loves all that is right, will do the same for them. But if one does not forgive, he would be asking, in the Our Father, that God not forgive him! Matthew 7:2 adds:" Whatever measure you use [in treating others], the same measure will be used on you."

The Sixth Beatitude: "Blessed are the pure in heart, for they shall see God."

The purity spoken of here is complete moral purity — not merely purity in sexual matters. Psalm 24. 3-4 asks who may stand in His holy place and answers: "The clean in hands, and pure in heart." Just as much sin dims one's perception of spiritual things, so constant adherence to what is morally right makes spiritual eyesight grow clearer.

The Seventh Beatitude: "Blessed are the peacemakers, they shall be called children of God."

Hebrew shalom means not only peace, but well-being in general. The angels at the birth of Christ announced peace. After His resurrection He told the Apostles: "Peace be with you." This includes our right relation with God, and with one another. Those who work for this, cooperate in the work of Christ, and so are His brothers, children of the Father.

The Eighth Beatitude: "Blessed are those who are persecuted for the sake of what is right: theirs is the Kingdom of Heaven."

St. Paul told the Romans (8:17): "We are heirs together with Christ, provided we suffer with Him, so we may also be glorified with Him." The Church from the beginning has seen the special application of this verse to the martyrs. Many in the first centuries thought only martyrs would reach the vision of God at once, others would wait until the end of time. We know others need not wait till then, if they have been purified and paid their debts. But the beatitude applies not only to martyrs, but to all who suffer for Christ, for what is right.

2. Special ideals in the Sermon on the Mount

Jesus gives many striking ideals in this sermon, e.g., in 5:25-26, 39-42 He urges us to settle peacefully with an opponent, to give no resistance to injury, to even turn the other cheek, to give even one's coat in addition to the shirt, to go two miles when asked for one. It is important to notice that these are not outright commands, but ideals, such that we should be inclined in these directions. But at times it is best to do otherwise, e.g., Jesus Himself in the Jewish court, when struck on the face, did not turn the other cheek, but rebuked the servant (John 18:22-23). St. Augustine, as quoted by St. Thomas Aquinas (II-II. 40. 1 ad 1) explains: "These things are always to be observed in readiness of soul. But at other times, one must act otherwise for the sake of the common good", or to restrain evildoers.