MCSause, Mason Here

Experience.

You can get it by killing mobs, smelting, and more. But where did it come from?

Well, In 1993, While mining, instead of dropping chocolate like most ores did at the time, Dinnar Bonne got these yellow orbs. He caculated that these orbs help you enchant things instead of eating chocolate to get the enchants.
He said:

ER MEH GERD I FOUND XP IM THE FIRST LOL ROFL LMFAO OH YEAH

ahem, well he jumped a little bit.

He showed Notch them

He liked them and then gave Mr. Bonne the nobel peace prize.

The end