The Continental Congress left no record of why the colors were chosen for the American flag. However, in 1782, the Congress of the Confederation chose the same colors for the Great Seal of the United States, and listed their meanings as:
Red represents hardiness and valor, qualities the new nation needed to stand up to the British government.
White means purity and innocence, an apt symbol for the birth of a new nation.
Blue symbolizes vigilance, perseverance and justice, the qualities of a democratic government.