Why was it important to bring two states into the union under the terms of the Missouri compromise ?

meant to create balance between slave and non-slave states

Explanation:

In 1820, amid growing sectional tensions over the issue of slavery, the U.S. Congress passed a law that admitted Missouri to the Union as a slave state and Maine as a free state, while banning slavery from the remaining Louisiana Purchase lands located north of the 36º 30' parallel.

They created powerful merchants by promoting enterprises in exchange for financial support, also they expanded territory though royal authority at the expense of the catholic church and through marriage.
On top of that, the religions that is adopted by the European monarchs persuade its followers to make some sort of 'offerings' for the sake of religious institutions that eventually is used as additional assets for the monarch to advance its trading.