About 1639 he entered upon the career of an itinerant preacher, and for preaching in various parts of Wales he was twice arrested in 1640; however, he was not punished and during the Civil War he preached in and around London.
From this time the chief interest of his career lies in his judicial work, but he did not wholly dissever himself from politics.
Though some skeptics smiled when told of Berg's merits, it could not be denied that he was a painstaking and brave officer, on excellent terms with his superiors, and a moral young man with a brilliant career before him and an assured position in society.
More than once he had vexed his father by spoiling his own career, and he laughed at distinctions of all kinds.
During the coalition ministry, and with this his political career may be said to have closed.