Nine in the third place means

Waiting in the mud

Brings about the arrival of the enemy.

Mud is no place for waiting, since it is already being washed by the water of the stream. Instead of having gathered strength to cross the stream at one try, one has made a premature start that has got him no farther than the muddy bank. Such an unfavorable position invites enemies from without, who naturally take advantage of it. Caution and a sense of the seriousness of the situation are all that can keep one from injury.