This statement seems a fairly straightforward observation: yes, it is true. There's not that much to be said about it directly.
However, it can tell us a lot about Shylock, and about Shakespeare. Look at the gap between words and emotion at other places in the play, including those spoken by Shylock. He should know that there is a gap between words and meaning, but here he seems not to. This may indicate a gap between how he sees spoken words and how he sees written words.
It also shows that Shylock has a kind of reverence for the written word. Perhaps this is Shakespeare's way of showing a dignity in his soul. Perhaps it is a suggestion of a religious attitude. It seems, though, to show Shakespeare's lack of real awareness of Judaism. There is a long tradition of laws requiring learned interpretation with Judaism, and Shylock should expect this.
Shylock thought that he would get his pound of flesh and revenge on Antonio because the law was steadfast. It was only because Portia figured out a way to make that impossible (because of the blood) so Shylock attempts to just take the money. This too, becomes impossible because of Portia, not only does she refuse him the money, but she quotes a law that says, " Portia produces another law, decreeing that if any foreigner “by direct or indirect attempts/ …seek[s] the life of a citizen,” he loses half his goods to the citizen, the other half to the state, and his “life lies in the mercy/ Of the Duke…” Shylock was sure at the beginning of the trial that the law was secure and he would have his revenge. Only after clever Portia takes them into her own hands do we see that this is not true.