The Emancipation Proclamation, excerpt

BY THE PRESIDENT OF THE UNITED STATES OF AMERICA.
A PROCLAMATION.

I, ABRAHAM LINCOLN, President of the United States of America, and Commander-in-Chief of the Army and Navy thereof, do hereby proclaim and declare that hereafter, as heretofore, the war will be prosecuted for the object of practically restoring the constitutional relation between the United States, and each of the States, and the people thereof, in which States that relation is, or may be, suspended or disturbed.

That it is my purpose, upon the next meeting of Congress to again recommend the adoption of a practical measure tendering pecuniary aid to the free acceptance or rejection of all slave States, so called, the people whereof may not then be in rebellion against the United States and which States may then have voluntarily adopted, or thereafter may voluntarily adopt, immediate or gradual abolishment of slavery within their respective limits; and that the effort to colonize persons of African descent, with their consent, upon this continent, or elsewhere, with the previously obtained consent of the Governments existing there, will be continued.

That on the first day of January in the year of our Lord, one thousand eight hundred and sixty-three, all persons held as slaves within any State, or designated part of a State, the people whereof shall then be in rebellion against the United States shall be then, thenceforward, and forever free; and the executive government of the United States, including the military and naval authority thereof, will recognize and maintain the freedom of such persons, and will do no act or acts to repress such persons, or any of them, in any efforts they may make for their actual freedom.

That the executive will, on the first day of January aforesaid, by proclamation, designate the States, and part of States, if any, in which the people thereof respectively, shall then be in rebellion against the United States; and the fact that any State, or the people thereof shall, on that day be, in good faith represented in the Congress of the United States, by members chosen thereto, at elections wherein a majority of the qualified voters of such State shall have participated, shall, in the absence of strong countervailing testimony, be deemed conclusive evidence that such State and the people thereof, are not then in rebellion against the United States.

That attention is hereby called to an Act of Congress entitled "An Act to make an additional Article of War" approved March 13, 1862, and which act is in the words and figure following:

‘‘Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That hereafter the following shall be promulgated as an additional article of war for the government of the army of the United States, and shall be obeyed and observed as such:

Article —. All officers or persons in the military or naval service of the United States are prohibited from employing any of the forces under their respective commands for the purpose of returning fugitives from service or labor, who may have escaped from any persons to whom such service or labor is claimed to be due, and any officer who shall be found guilty by a court-martial of violating this article shall be dismissed from the service.

SEC. 2. And be it further enacted, That this act shall take effect from and after its passage."

What is Lincoln’s purpose in writing this document?
To explain the moral reasons for abolishing slavery
To outline the practical effects of abolishing slavery
To force Congress to convene to abolish slavery
To force Congress to convene to end the Civil War