Kuzan asked Garp if he's able to kill a former student. Garp responded by chucking his ass(going off on a tangent here, but Blue Hole is the greatest attack in manga history) and saying those who hesitate are weak. Later, Kuzan was asking Garp to stand down because he's concerned about his condition, and Garp called him soft, with Kuzan being shocked that Garp could still move like that.
Garp didn't give a shit, but Kuzan hesitated.