"That the righteousness of the law might be fulfilled in us, who walk not after the flesh but after the Spirit." (Romans 8:4)
Our text does not say fulfilled BY us, but IN us, and there is a great difference between the two. An illustration will make this difference clear. We are at a boarding school for boys, and at half-past six on a dreary December morning the school bell clangs insistently. It says, "Get up, get up," and one hundred sleepy boys slip reluctantly from their beds. They hate the sound of that bell at that hour, and obey its command with great reluctance and only because they must. The law of the school is fulfilled by them, not because they love it, but from fear of the consequences of disobedience.
But at half-past twelve on that same day that same bell rings again, and its ringing is just as much a command as it was in the early morning, but how different is the sound of it to those same boys. It is now as pleasant to them as before it was hateful; they have been longing to hear it for more than an hour, and everything is dropped with which they are engaged and a rush is made to the Dining Room. The command of the dinner bell is fulfilled IN them, for there is that in them that gives an instant response to it.
If the righteousness of the law is to be fulfilled in us, there must be in us a nature that responds to it. When we were "in the flesh" i.e., in our natural unregenerated state, we had no such nature and we did not and could not please God, our very nature was enmity against Him, as our chapter tells us. But now, having believed the gospel, we are "in Christ Jesus." What a change! And the law of the Spirit of life in Christ Jesus can make us free from the law of sin and death, so that we may delight now in the law of God after the inward man, and find a power in the Spirit to fulfil it. The law said, "Thou shalt love the Lord thy God," and we do love Him, for He has first loved us. He has "commended His love to us in that while we were yet sinners Christ died for us," and we belong to those who in this chapter are called "them that love God." The command to love Him is not grievous; we delight in it, and as we live in the love of God, just as the lark lives in the sunshine, we enjoy the liberty of the Christian life; we know what it is to be on the wing, set free, and our lives will be full of the praise of God.