And he opened his mouth
Having announced the kingdom of heaven as "at hand," the King, in Matthew 5-7, declares the principles of the kingdom. The Sermon on the Mount has a twofold application:
(1) literally, to the kingdom. In this sense it gives the divine constitution for the righteous government of the earth. Whenever the kingdom of heaven is established on earth it will be according to that constitution, which may be regarded as an explanation of the word "righteousness" as used by the prophets in describing the kingdom (for example) (Isaiah 11:4-5); (Isaiah 32:1); (Daniel 9:24) In this sense the Sermon on the Mount is pure law, and transfers the offence from the overt act to the motive. (Matthew 5:21-22); (Matthew 5:27-28). Here lies the deeper reason why the Jews rejected the kingdom. They had reduced "righteousness" to mere ceremonialism, and the Old Testament idea of the kingdom to a mere affair of outward splendour and power. They were never rebuked for expecting a visible and powerful kingdom, but the words of the prophets should have prepared them to expect also that only the poor in spirit and the meek could share in it (for example) (Isaiah 11:4). The seventy-second Psalm, which was universally received by them as a description of the kingdom, was full of this. For these reasons, the Sermon on the Mount in its primary application gives neither the privilege nor the duty of the Church. These are found in the Epistles. Under the law of the kingdom, for example, no one may hope for forgiveness who has not first forgiven. (Matthew 6:12); (Matthew 6:14); (Matthew 6:15). Under grace the Christian is exhorted to forgive because he is already forgiven. (Ephesians 4:30-32).
(2) But there is a beautiful moral application to the Christian. It always remains true that the poor in spirit, rather than the proud, are blessed, and those who mourn because of their sins, and who are meek in the consciousness of them, will hunger and thirst after righteousness, and hungering, will be filled. The merciful are "blessed," the pure in heart do "see God." These principles fundamentally reappear in the teaching of the Epistles.
saying
The beatific character, unattainable by effort, is wrought in the believer by the Spirit, (Galatians 5:22-23).