One verse captures the essences of the Sermon on the Mount: “Be perfect, therefore, as your heavenly Father is perfect.”[1] The Sermon has a primary purpose and a secondary purpose. The primary purpose is to tell us that God’s Law is exceedingly broad. The secondary purpose is to set the stage for the New Covenant.

The Pharisees thought that they had satisfied the demands of the Law by their outward righteous. They did not murder, did not break their oaths, did not commit adultery, and if they divorced their wives they followed the proper procedures.[2] But their mistake was to think that the Law only applied to their outward actions. It applied to their thoughts and feelings as well. It is not good enough to simply not murder; anger itself is prohibited.[3] They were also mistaken to think that the Law only required them to do so much and no more, like a chore to get out of the way before one can relax. Instead, the Law requires everything a person has.[4] It requires not only your cloak, but also your tunic.[5] It requires not only one’s deeds, but also one’s thoughts.[6] The Law never allows a person to say that she has done quite enough and need do no more.[7] It is God’s law, not man’s, and although man judges the outside, God judges the heart.[8] Even today, we should still be careful not take this a legalistic attitude toward God’s commands, as if we were doing our taxes and looking for every technicality to allow us to pay the IRS as little as possible without getting into trouble.

Once we understand the true requirements of the law, we cannot help but fall under the heavy conviction that it is impossible for us to meet these requirements. In this way, the Law forces us to trust in Christ.[9] Once, we might have thought that God might be happy enough with us because of our good behavior because we did not murder, commit adultery, steal, lie, cheat, and so on. But once we realize that God’s standard is perfection, and even perfection of thought and feeling, we must see that we cannot meet this standard – before it we are unworthy. Our feeling is like the Apostle John’s in Revelation when the sealed scroll of God was displayed and the angel asked ‘who is worthy to break the seals and open the scroll?’ but no one in heaven or on earth or under the earth could was worthy; at this, John “wept and wept because no one was found who was worthy to open the scroll…”[10] If the Sermon on the Mount were the last divine word to us, our only response could be to weep and weep, because no one would be found worthy before the law of God. But, rejoice! We receive the same answer that the Apostle did: “Do not weep! See, the Lion of the tribe of Judah, the Root of David, has triumphed. He is able to open the scroll and its seven seals.”[11] When we were unable to live up to God’s standard, Christ was able. The Law was unable to make us righteous, as we were unable to meet its requirements. But Christ was able to meet its requirements, and so God made us righteous through Christ.[12]
[1] Matt. 5:48.
[2] See Matt. 5:21, 27, 31, 33.
[3] Matt. 5:22.
[4] Matt. 22:37-40.
[5] Matt. 5:40.
[6] Matt. 5:21-30.
[7] Matt. 5:42.
[8] 1 Sam. 16:7.
[9] Gal. 3:24-25
[10] Rev. 5:1-4.
[11] Rev. 5:5.
[12] Rom. 8:3-4.