He was strongly opposed to the Conventicle and Five Mile Acts.
The Quaker Act 1662 and the Conventicle Acts of 1664 and 1670, designed to enforce attendance at church, and inflicting severe penalties on those attending other religious gatherings, were responsible for the most severe persecution of all.
In1652-1654and1658-1662Biddle held a Socinian conventicle in London; in addition to his own writings he reprinted (1651) and translated (1652) the Racovian Catechism, and the Life of Socinus (1653).
In Carthage, for example, it would appear that the breach between the Catholic Church and the Montanistic conventicle was caused by a disagreement on the question whether or not virgins ought to be veiled.
Under the Quaker Act of 1662 and the Conventicle Act of 1664 a number were transported out of England, and under the last-named act and that of 1670 (the second Conventicle Act) hundreds of households were despoiled of all their goods.
Hence the Conventicle Act (1664) imposed penalties on those taking part in religious meetings in private houses, and the Five Mile Act (1665) forbade an expelled clergyman to come within five miles of a corporate borough, the very place where he was most likely to secure adherence, unless he would swear his adhesion to the dbctrmn.e of non-resistance.
He was indeed taken in June 1673 while holding a conventicle at Knockdow, and condemned by the privy council to 4 years and 3 months' imprisonment on the Bass Rock and a further 15 months in the Tolbooth at Edinburgh.
Opposition from a master potter of the district, who threatened to put the Conventicle Act in force, was overcome, but more serious difficulties were presented by the antagonism of the Wesleyan Methodist circuit authorities.