What does it mean by "bondsman's two hundred and fifty years of..." in Lincoln's 2nd inaugural adress?

I'm not sure who is the bondsman and why his wealth matters here.

Here is the quote, from the paragraph of Lincoln's Second Inaugural Address

Yet, if God wills that it continue until all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil shall be sunk, and until every drop of blood drawn with the lash shall be paid by another drawn with the sword, as was said three thousand years ago, so still it must be said "the judgments of the Lord are true and righteous altogether.

Solution 1:

He is referring to slavery; bondsman - a male slave

President Lincoln’s Second inaugural Address , 1865:

• Just 701 words long, Lincoln’s Second Inaugural Address took only six or seven minutes to deliver, yet contains many of the most memorable phrases in American political oratory. The speech contained neither gloating nor rejoicing. Rather, it offered Lincoln’s most profound reflections on the causes and meaning of the war. The “scourge of war,” he explained, was best understood as divine punishment for the sin of slavery, a sin in which all Americans, North as well as South, were complicit. It describes a national moral debt that had been created by the “bondsmen’s 250 years of unrequited toil,” and ends with a call for compassion and reconciliation.

(from www.gilderlehrman.org)

Solution 2:

"all the wealth piled by the bondsman's two hundred and fifty years of unrequited toil" refers to the material gains extracted from the labors of the African slaves brought to North America continuously from 1619 to 1864. A "bondsman" in the common parlance of the day was a slave, and Lincoln was well aware that slaves had been instrumental in the building of America from the very start. He also knew that money and loot might not be enough to atone for our sins, hence the further warning that the war might need to continue until "every drop of blood drawn with the lash shall be paid by another drawn with the sword". Explaining it thusly leaves nobody off the hook - slavery is the sin of us all, not simply the South. So be it.