Answer: unite the colonists in support of continuing the fight for independence
Step-by-step explanation:
Here's the excerpt:
"I call not upon a few but upon all—not on this state or that state, but on every state—up and help us. . . . Let it be told to the future world that in the depth of winter, when nothing but hope and virtue could survive, that the city and the country, alarmed at one common danger, came forth to meet and repulse it."
The purpose of Paine in issuing this plea is to unite the colonists in support of continuing the fight for independence.
This can be seen in the excerpt as it was inferred that everyone was called to come together and help and repulse the fight for their independence.