The problem with the law, even though it’s an expression of God’s wisdom, will, love, and holiness and is therefore spiritual, holy, and good itself, is that it cannot, *by *itself, transform us into His image. It cannot produce holiness, but only affords an external “show” of it to the extent that we obey it with hearts that aren’t changed, that are not operating out of the right motivation. This is why Jesus tells us that our righteousness must *exceed *that of the Scribes and Pharisee, religious leaders who were generally looked up to as moral icons of the day.
He tells us that something is missing in man, and that we cannot achieve it to the extent that we’re apart from Him, apart from *God. *Man was made for authentic communion with God, and this communion begins with faith. Then He can do a work in us, as per the New Covenant promises of Jer 31:33-34, transforming us into His image. This righteousness, this justice, is defined as love, which fulfills the law by it’s very nature. (Rom 13:8) This is why the greatest commandments are what they are and this is what it means to fulfill the law by the Spirit rather than by the letter.