Paine says that during the retreat over the Delaware, the Continental troops desperately hoped for help from people in the countryside:
All their wishes centered in one, which was, that the country would turn out and help them to drive the enemy back.
So a major part of his message is to rally people to join the cause. But his tone is not that of desperation. Rather, in the face of the apparent setbacks, he attempts to show that all will not be lost even if General Howe captures Philadelphia and wins a major military victory over Washington's army. What he does say, though, is that those who do not rally to the cause will regret it later:
The heart that feels not now is dead; the blood of his children will curse his cowardice; who shrinks back when a little might have saved the whole...
So his appeal is more to individual honor than to military exigency. He does not say that the army will perish without the help of the people, but rather that the people will have missed a chance to take part in something unique in history if they do not join the cause.