First of all however the internal agitation became prominent, increasing in proportion as the settlement of external affairs failed to correspond with the expectations which had been cherished.

On the one side the Presbyterians, who had been till now suppressed, rose up again in great force. Amongst other things the pestilence helped them, in so far as it provided scope once more for the spiritual activity of their preachers. Their old religious zeal revived; the public need and the natural duty of religion seemed in themselves to abolish the interdict under which they languished; for no law promulgated by mortal man would excuse them if they should willingly neglect the care for the immortal soul of a dying brother. Whilst the Anglican clergy fled, the Presbyterian preachers mounted once more the pulpits, to announce to the people, ere they were snatched away, the words of eternal salvation; never had they spoken so convincingly, never been listened to so reverently. The consideration which they again won by this means, their growing consciousness of strength, and the fear of their co-operation with the enemy without in any emergency that might occur, caused the Parliament in Oxford, under the impression produced by conspiracies recently discovered, to establish a formula—a shibboleth, as it was called—in order to distinguish those who were dangerous amongst the Nonconformists, from those who could be tolerated.