20. 以利動之以卒待之
By holding out baits, he keeps him on the march; then with a body of picked men he lies in wait for him.
This would appear to be the meaning if we retain 卒, which Mei Yao-ch‘ên explains as 精卒 “men of spirit.” The T‘u Shu reads 本, an emendation suggested by 李靖 Li Ching. The meaning then would be, “He lies in wait with the main body of his troops.”
21. 故善戰者求之於埶不責於人故能擇人而任埶
The clever combatant looks to the effect of combined energy, and does not require too much from individuals.
Tu Mu says: “He first of all considers the power of his army in the bulk; afterwards he takes individual talent into account, and uses each man according to his capabilities. He does not demand perfection from the untalented.”
Hence his ability to pick out the right men and to utilise combined energy.
Another reading has 之 instead of 埶. It would be interesting if Capt. Calthrop could tell us where the following occurs in the Chinese: “yet, when an opening or advantage shows, he pushes it to its limits.”
22. 任埶者其戰人也如轉木石木石之性安則靜危則動方則止圓則行
When he utilises combined energy, his fighting men become as it were like unto rolling logs or stones. For it is the nature of a log or stone to remain motionless on level ground, and to move when on a slope; if four-cornered, to come to a standstill, but if round-shaped, to go rolling down.