The British and the German soldiers (called Hessians) did not expect George Washington to cross the Delaware River. It was the winter of 1776. It was freezing. And the river was full of big chunks of ice and wild currents of water. So, no one was patrolling the river banks.
On Christmas eve, Dec 24, 1776, George Washington decided to cross the river and attack. As he crossed the river, his men pushed huge ice chunks out of their way. Washington's plan was successful. The colonists captured 900 Hessian soldiers. No colonists were killed in battle. Only 4 colonists were wounded.
On Jan 3, 1777, Washington engaged in the Battle of Princeton, which he also won!
The success of these two battles pretty much recovered New Jersey for the colonists.
Success lifted spirits. It gave heart to the militia. Most of Washington's troops were going to leave soon. Their term of enlistment had actually ended a few days earlier on Jan 1, 1777. Washington asked the men to stay. He offered a re-enlistment bonus of $10 (about 2 months pay) to any militiaman who would sign on for another six months. About half the men agreed to reenlist.
After he made this offer, Washington had to convince the Continental Congress to approve and pay the bonus. Washington had overstepped his authority. But Congress agreed, approved, and paid.