Summary: We willingly accept the blessings of the Beatitudes, but must also embrace the responsibilities.
THE BLESSINGS OF THE CHRISTIAN
The Sermon on the Mount is directed towards those who are already disciples of Jesus (Matthew 5:1). This is important. It counters both those religious hopefuls who find the Beatitudes impossible to keep, and those religious moralists who glibly announce “I live by the Sermon on the Mount.”
In Adam we cannot attain the ideals of this code of life, but in Christ we can. In Adam it is as law to us, and only highlights our inability to keep the law. This teaching belongs to the Christian.
Sometimes the Sermon on the Mount has been the called the new Law. This is not necessarily helpful. We are not under law, but under grace.
Those who are joint-heirs with Christ do not strive to enter into the kingdom of heaven by good works, for they are already its citizens. On the contrary, they demonstrate their faith by their works (James 2:18). The believer is saved by faith not by works, but is nevertheless saved unto good works (Ephesians 2:8-10).
The poor in spirit, according to the text in front of us, are already in possession of the kingdom of heaven (Matthew 5:3). They are already enabled to fulfil the obligations of the Sermon. The rewards throughout these verses are rewards of grace, not of merit.
All the Beatitudes belong to all of Christ's people, not just to an elite few. These words are for the church of Jesus Christ, built upon the rock. These words are for the redeemed, for those who are salt and light. We willingly accept the blessings, but must also embrace the responsibilities.
The followers of Jesus are the poor in spirit, who mourn for their sins. They are the meek, who hunger and thirst after righteousness. They are merciful, and pure-hearted; peaceful, yet persecuted.
It is they who possess the kingdom of heaven, and shall receive comfort. They are the true heirs of the earth, and shall be satisfied. They shall obtain mercy, and meet with God face to face. They shall be revealed as the true sons of God, and are possessors of heaven itself.
To be blessed is to be endowed with divine favour. It is to be proclaimed holy. Some people translate the corresponding Greek word in terms of happiness, but it is much more than that. The pursuit of happiness without holiness is futile. The Beatitudes relate what Christians are in Christ, and pronounces the blessings which belong solely to them.
The poor in spirit (Matthew 5:3)
The poverty spoken of here is not lack of bread or of rice. It refers rather to that humility of spirit which recognises our emptiness without Christ. Those who imagine themselves to have no need of Christ are sent away empty (Luke 1:53).
Self-righteousness prays within itself as if all its spiritual needs could be met through self-sufficiency. True poverty of spirit cries with the publican in Jesus' parable, “God be merciful to me, the sinner” (Luke 18:11-13).
The spiritually poor have the gospel preached to them (Luke 4:18). This preaching was one of the marks of Jesus' Messiah-ship. John the Baptist was reminded of this during his incarceration (Luke 7:22).