https://en.wikipedia.org/wiki/George_Washington%27s_Farewell_Address#Political_parties said:
Washington continues to advance his idea of the dangers of sectionalism and expands his warning to include the dangers of political parties to the country as a whole. These warnings are given in the context of the recent rise of two opposing parties within the government—the Democratic-Republican Party led by Jefferson, and Hamilton's Federalist Party. Washington had striven to remain neutral during a conflict between Britain and France brought about by the French Revolution, while the Democratic-Republicans had made efforts to align with France and the Federalist had made efforts to ally with Great Britain.
Washington recognizes that it is natural for people to organize and operate within groups such as political parties, but he also argues that every government has recognized political parties as an enemy and has sought to repress them because of their tendency to seek more power than other groups and to take revenge on political opponents. He feels that disagreements between political parties weakened the government.
Moreover, he makes the case that "the alternate domination" of one party over another and coinciding efforts to exact revenge upon their opponents have led to horrible atrocities, and "is itself a frightful despotism. But this leads at length to a more formal and permanent despotism." From Washington's perspective and judgment, political parties eventually and "gradually incline the minds of men to seek security... in the absolute power of an individual", leading to despotism. He acknowledges the fact that parties are sometimes beneficial in promoting liberty in monarchies, but argues that political parties must be restrained in a popularly elected government because of their tendency to distract the government from their duties, create unfounded jealousies among groups and regions, raise false alarms among the people, promote riots and insurrection, and provide foreign nations and interests access to the government where they can impose their will upon the country.