The. Strength of the wolf is the pack. What dose it mean?

The "wolf" draws strength from its brother (or sister) wolf pack members...strength in numbers....

It means that no matter how strong the wolf is Von itself and no matter how much power and force it has Von itself, the whole sense of a pack and all the Wölfe working together as one strengthens the bond between them and makes them so so much stronger plus gives a sense of teamwork and power even more.

The main strength of the Werwölfe is in numbers and in the teamwork and co-ordination their mental link gives them.