Why we must allow ourselves to be crushed by the Law of God

Why then do you preach the law?
Because it is a schoolmaster to bring people to Christ.
It teaches them the nature of sin, and convinces them of their want of a Saviour. “By the law is the knowledge of sin,” Rom. iii. 20; and vii. 7. Men are secure and careless in sin, until the law, that worketh wrath, reach their consciences, then they begin to know sin, and to feel the exceeding sinfulness of it: “for it is the ministration of condemnation.” 2 Cor. iii. 9.
This then is the office of the law. It brings transgressors to the knowledge of sin, condemns them for it, and puts them under the sentence of their guilt and of their danger, they then find their want of a Saviour.
The law, spiritually understood and applied, convinces the sinner that he is a condemned creature, shows him in God’s word the sentence past upon him, and makes him dread the execution of it. And thus it becomes to him, “the ministration of death,” 2 Cor. iii. 7, proving him to be guilty of sin, and to be deserving of death.
The apostle’s case is very common. I thought myself alive, says he, without the law; he had no doubt but he was alive to God, while he was a strict Pharisee; but when the holy spiritual nature of the law was made known to him, he found himself to be dead in trespasses and sins.
This then is the office of the law. It brings transgressors to the knowledge of sin, condemns them for it, and puts them under the sentence of their guilt and of their danger, they then find their want of a Saviour.
But without this work of the law, they would not have been sensible that they stood in need of Him. If they were never sick, they would never send for the physician. If they were never brought to the knowledge of sin, they would never desire the knowledge of a Saviour. If they never found themselves under guilt and condemnation, they would never sue for His pardon, and would never ask life of Him, unless they found that they deserved to die the first and the second death.
For these reasons the law must be taught. It is the schoolmaster appointed of God to bring sinners (both justified sinners and unjustified sinners!) unto Christ, and when the schoolmaster comes in the name and power of the divine Spirit, and convinces them of their distressed state and condition, and makes them sensible of their guilt and of their misery, then He brings them to Christ, earnestly to ask and humbly to receive mercy from Him, who is the end of the law for righteousness to every one that believeth. ---William Romaine