Use the passage to answer the question that follows:

in the summer of 1863,

southern and northern troops clashed in one of the bloodiest battles of the civil war. after the confederate, or southern, army won a battle in northern virginia, it invaded the north and headed into pennsylvania. it hoped to collect more supplies and weaken the north. meanwhile, the union army of the north was pursuing the confederate troops. the two sides met and fought near the town of gettysburg, pennsylvania. the battle at gettysburg has been called “the most crucial battle in american history.” before the battle of gettysburg, the confederacy had been doing very well in the civil war. but at gettysburg, the north defeated the south. the battle was bloody. the union army suffered 23,000 casualties, while the confederate army suffered 28,000. a casualty is someone who is killed, wounded, or captured in battle. the battle of gettysburg turned the tide of the war and marked the beginning of the success of the north in defeating the south. in the fall of 1863, president lincoln visited the battlefield at gettysburg for a ceremony dedicating the field to all the soldiers who had died. he reminded people why americans must stand up for their values. his speech, the gettysburg address, has become one of the most famous speeches of american history. lincoln said: “four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty, and dedicated to the [idea] that all men are created equal. now we are engaged in a great civil war, testing whether that nation or any nation so conceived and so dedicated, can long endure. we are met on a great battlefield of that war. we have come to dedicate a portion of that field, as a final resting place for those who here gave their lives that that nation might live. it is altogether fitting and proper that we should do this. but, in a larger sense, we can not dedicate—we can not consecrate—we can not hallow—this ground. the brave men, living and dead, who struggled here, have consecrated it, far above our poor power to add or detract. the world will little note, nor long remember what we say here, but it can never forget what they did here. it is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. it is rather for us to be here dedicated to the great task remaining before us—that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain—that this nation, under god, shall have a new birth of freedom—and that government of the people, by the people, and for the people, shall not perish from the earth.” lincoln’s words were never forgotten. the government of the people, by the people, and for the people remains.

question: what is the "great task" described in the gettysburg address?