The North was extremelyindustrialized while the South relied heavily on slavery and agriculture. The North often bought food from the South due to the poor conditions of soil in the North. This was how the South contributed to the economy and continued using slaves up until the events of the Civil War.
Due to the North having no need for slave labor and instead freeing the slaves, Northerners tended to protest against the use of slavery and found distaste in it. Meanwhile, in the South, Southerners relied very much on slave labor and, as a result, saw it as okay and wanted slavery to stay. The government was trying very hard to compromise, but slavery clearly isn't an issue that you can compromise on.
