3. Instrumental.—As, I fight with a sword=pugno ense=feohte sweorde,—Anglo-Saxon.
4. Emphatic.—As, he sleeps the sleep of the righteous.
[§ 560]. Verb and nominative case.—No verb governs a nominative case. The appositional construction seems to require such a form of government; but the form is only apparent.
It is I.
It is thou.
It is he, &c.
Here, although the word is is followed by a nominative case, it by no means governs one—at least not as a verb.
It has been stated above that the so-called verb substantive is only a verb for the purposes of etymology. In syntax, it is only a part of a verb, i. e., the copula.
Now this fact changes the question of the construction in expressions like it is I, &c., from a point of government to one of concord. In the previous examples the words it, is, and I, were, respectively, subject, copula, and predicate; and, as it is the function of the copula to denote the agreement between the predicate and the subject, the real point to investigate is the nature of the concord between these two parts of a proposition.