Why was slavery abolished in the north?

During the ensuing decades, the abolitionist movement grew in Northern states, and Congress regulated the expansion of slavery as new states were admitted to the Union. Britain banned the importation of African slaves in its colonies in 1807 and abolished slavery in the British Empire in 1833.

they knew all men were created equal. the south had some economy issues or whatever. im digging thru last years memory to answer this. but its a fact south ppl has had economy issues there.