On this day in history, President Abraham Lincoln issued a proclamation granting amnesty to all citizens of the rebellious southern states who would take an oath of loyalty to the Union and swear to abide by all Federal laws and proclamations in reference to slavery made during the period of the rebellion. Six classes of persons were excluded from the benefits of the amnesty:
Civil or diplomatic agents or officials of the Confederacy
Persons who left judicial posts under the United States to aid the rebellion
Confederate military officerrs above the rank of Army colonel or Navy Lieutenant
Members of the U.S.Congress who left to aid in the rebellion
Persons who resigned commissions in the U.S. ARmy or Navy and afterward aided in the rebellion
Persons who treated unlawfully black prisoners of war and their white officers.
However, the declaration of amnesty did not specify who would administer the oath to those southerners who desired to take it. On March 26, 1864, Lincoln issued another proclamation which designated “any commissioned officer, civil, military, or naval in the service of the United States” to administer the oath, as well as those persons in the territories which were “not in insurrection who were by the laws therefore qualified for administering oaths.” It also added a seventh exception to eligibility: persons in military or cvilian confinement or custody.
You can read a text of the December proclamation here.