The so-called “curse of Ham” was used by the southern slaveholder as a biblical justification to hold slaves. Here is the story as it’s found in Genesis 9:18-29:
18 And the sons of Noah, that went forth of the ark, were Shem, and Ham, and Japheth: and Ham is the father of Canaan.
19 These are the three sons of Noah: and of them was the whole earth overspread.
20 And Noah began to be an husbandman, and he planted a vineyard:
21 And he drank of the wine, and was drunken; and he was uncovered within his tent.
22 And Ham, the father of Canaan, saw the nakedness of his father, and told his two brethren without.
23 And Shem and Japheth took a garment, and laid it upon both their shoulders, and went backward, and covered the nakedness of their father; and their faces were backward, and they saw not their father’s nakedness.
24 And Noah awoke from his wine, and knew what his younger son had done unto him.
25 And he said, Cursed be Canaan; a servant of servants shall he be unto his brethren.
26 And he said, Blessed be the Lord God of Shem; and Canaan shall be his servant.
27 God shall enlarge Japheth, and he shall dwell in the tents of Shem; and Canaan shall be his servant.
28 And Noah lived after the flood three hundred and fifty years.
29 And all the days of Noah were nine hundred and fifty years: and he died.
Those who believed slavery should be abolished made passionate arguments against the supporters of slavery, who claimed that the “cursed” descendants of Ham had settled in Africa, were dark-skinned, and destined to subjugation.
When James A. Sloane published his pro-slavery treatise, The Great Question Answered; or Is Slavery a Sin in Itself? Answered According to the Teaching of the Scriptures, David R. Kerr, editor of The United Presbyterian Quarterly Review, gives Sloane credit for making the Bible “the only rule for faith and practice,” but then he slams him for his weak biblical arguments concerning the curse of Ham. At one point he laughs at the absurdity of Sloane’s position and proclaims: “Risum teneatis, amici?!” (Can you help laughing, my friends?!) 
Why was the pro-slavery teaching on the biblical “curse of Ham” so laughable to abolitionists?
- The only descendant who was cursed was Canaan. Genesis 9:25 says, “Cursed be Canaan.” It doesn’t say, “cursed be Ham.” According to Josiah Priest, writing in his book, Bible Defence of Slavery, the authority to expand the curse to Ham came from the Arabic translation of the Bible, not the Hebrew Bible itself:
“For an account of this appalling anathema, see Genesis ix, 24–27, as follows: “And Noah awoke from his wine, and knew what his younger son had done unto him: and he said, cursed be Canaan [Ham]; a servant of SERVANTS shall he be unto his brethren. And he said, blessed be the Lord God of Shem; and Canaan [Ham] shall be his servant. God shall enlarge Japheth, and he shall dwell in the tents of Shem; and Canaan [Ham] shall be his servant.”
But lest the reader should become perplexed, respecting the application of this anathema, on account of the text above referred to being, in the English, “cursed Canaan” instead of “cursed Ham,” as it should have been translated; we state that the Arabic copy of the book of Genesis, which is a language of equal authority with the Hebrew, and originally the very same, reads “cursed Ham,” the father of Canaan, a servant of servants shall he be unto his brethren. 
The pro-slavery defense took liberty with the scriptures by changing the word Canaan into Ham.*
- Ham’s descendants didn’t even settle in sub-Saharan Africa, the place from where southern slaves were taken. According to Genesis 10:6-20, Ham’s sons were Cush, Egypt, Put, and Canaan. The sons of Cush settled in Babylon (his son was Nimrod, the builder of the Tower of Babel), Egypt would become the father of the Egyptians and the Philistines, and Canaan would become the father of the tribes that spread from Sidon to Gaza to Sodom and Gomorrah. (The Amorites, Hivites, Jebusites, etc…) Put settled in modern Libya and north Africa.
- According to Sloane, the name “Ham” meant “black,” but Kerr argued that this was untrue. The word Ham is never used for the word black. Instead the Hebrew word used for black is “shachar” or “shachor.” The Hebrew word for Ham is “cham” and it means “hot.
The Bible was abused by the southern slaveholder. There is no “curse of Ham” found in the scriptures. Those who wanted to hold slaves for their own profit had to become biblical contortionists. There were two groups of “Christians” involved in the debate over slavery. One group was “rightly handling the word of truth(2 Tim. 2:15)” while the other used the Bible for “dishonest gain (1 Tim. 6:5).”
*Why would God be upset with Canaan’s descendants in the future? According to Leviticus 18, the Israelites were commanded to obey God and keep his ordinances and statutes. These ordinances included prohibitions against incest, adultery, child sacrifice, homosexuality, and bestiality. In verse 24 God explains:
“Do not defile yourselves by any of these things, for by all these the nations [the Canaanite tribes] I am casting out before you defiled themselves; and the land became defiled, so that I punished its iniquity, and the land vomited out its inhabitants.”
The Canaanite tribes were pagan idol worshipers. They didn’t follow any of the Judaic laws concerning cleanliness and sexual purity. Some abolitionists argued that the curse of Canaan was merely a prophecy given by Noah in regards to the behavior of the Canaanites and how God would have to respond to them in the future.
 David R. Kerr. “Article II: Sloan on Color and Slavery” The United Presbyterian Review, Volume 2. (Pittsburgh, PA: Publication Office, No. 76 Thirds St., 1861), 336. https://books.google.com/books?id=pdsZAAAAYAAJ&pg=PP9&dq=James+A.+Sloan+the+great+question+answered&source=gbs_selected_pages&cad=3#v=onepage&q=James%20A.%20Sloan%20the%20great%20question%20answered&f=false
 Josiah Priest, Bible Defense of Slavery. (LOUISVILLE, KY: J. F. BRENNAN, 1851). accessed 8/30/2017 at https://theedixieflatline.wordpress.com/2014/12/10/bible-defence-of-slavery-part-two/#comment-27372.
For once, we’re pretty-much in agreement. The attempt to portray Noah’s cursing of Canaan as being a curse on Ham and his descendants is… well it’d be laughable if the purpose wasn’t so sickening.
This series of posts on my own blog may be of interest; though if you decide to read the book I was working on (Bible Defence Of Slavery by Joseph Priest) rather than just my introductory blatherings, I would suggest having strong drink to hand. It really is not nice.