Cromwell, as we have said, is the best commentator Isaiah has ever had, and that by an instinct born, not only of the same faith, but of experience in tackling similar sorts of character. In this letter he is dealing, like Isaiah, with stubborn pedants, who are endeavouring to fasten the national fortunes upon a Procrustean policy. The diplomacy of Jerusalem was very clever; the Covenanting ecclesiasticism of Edinburgh was logical and consistent. But a Jewish alliance with Assyria and the attempt of Scotsmen to force their covenant upon the whole United Kingdom were equally sheer impossibilities. In either case _the bed was shorter than that a man could stretch himself on it, and the covering narrower than that he could wrap himself in it_. Both, too, were covenants with Death and Hell; for if the attempt of the Scots to secure Charles II. by the Covenant was free from the falsehood of Jewish diplomacy, it was fatally certain if successful to have led to the subversion of their highest religious interests; and history has proved that Cromwell was no more than just in applying to it the strong expressions, which Isaiah uses of Judah's ominous treaties with the unscrupulous heathen. Over against so pedantic an idea, as that of forcing the life of the three nations into the mould of the one Covenant, and so fatal a folly as the attempt to commit the interests of religion to the keeping of the dissolute and perjured king, Cromwell stands in his great toleration of everything but unrighteousness and his strong conviction of three truths:--that the religious life of Great Britain and Ireland was too rich and varied for the Covenant: that national and religious interests so complicated and precious could be decided only upon the plainest principles of faith and justice: and that, tested by these principles, Charles II. and his crew were as utterly without worth to the nation and as pregnant with destruction, as Isaiah felt Assyria and Egypt to be to Judah. The battle-cries of the two parties at Dunbar are significant of the spiritual difference between them. That of the Scots was "The Covenant!" Cromwell's was Isaiah's own, "The Lord of hosts!" However logical, religious and sincere theirs might be, it was at the best a scheme of men too narrow for events, and fatally compromised by its association with Charles II. But Cromwell's battle-cry required only a moderately sincere faith from those who adopted it, to ensure their victory. For to them it meant just what it had meant to Isaiah, loyalty to a Divine providence, supreme in righteousness, the willingness to be guided by events, interpreting them by no tradition or scheme, but only by conscience. He who understands this will be able to see which side was right in that strange civil war, where both so sincerely claimed to be Scriptural.