需于泥致寇至.
Ni 泥: mud. The Shanghai Museum MS has ni 坭 which is a known variant of 泥. The character also means ‘to be obstructed, to be held up’, like being stuck in the mud.
Zhi 致: cause something to arrive (使達到), to make it dispatch.
Zhi 至: arrive.
Waiting in the mud will make invaders come.