An important American work. Wylie was a member of the Reformed Presbyterian deeply informed by the Scottish Covenanters and their National Covenant. In 1802, Thomas Jefferson wrote to the Danbury Baptist Association and used, for the first time, the phrase "separation of church and state." Wylie's book, first released in 1803, refuted Jefferson's claims, arguing that the two sons of oil in Zechariah are Ministers of the Gospel and the Magistrates of the Government and that they both need to be in faithful covenant with God. 

This edition contains an additional essay on submission to the government [1850] which seems to have the Fugitive Slave Act in mind. 

Wylie, Samuel B. The Two Sons of Oil; Or, The Faithful Witness for Magistracy and Ministry Upon a Scriptural Basis. By Rev. Samuel B. Wylie, A.M. Third Edition. With An Essay on Submission to Civil Government. Philadelphia. WM. S. Young, Printer. 1850. 120pp.

A good + copy, bound in cloth wraps, generally solid, with moderate foxing.