Remarks to Rump Parliament, 20 Apr. 1653. The Oxford Dictionary of Quotations describes this as "oral tradition." BulstrodeWhitlocke, Memorials of the English Affairs (1682), describes Cromwell as telling the House that "they has sate long enough, unles they had done more good."
Christopher Columbus, Robert Venables, Oliver Cromwell, Thomas Modyford (Sir.), Nevil (of Jamaica.) (1800). “Interesting tracts, relating to the island of Jamaica: consisting of curious state-papers, councils of war, letters, petitions, narratives, &c. &c., which throw great light on the history of that island, from its conquest down to the year 1702”, p.44