What is Rosh's main requirements for those who wish to join his band?
One of Rosh's main requirements for the men and boys who join him is that they do not have "a soft streak." He accuses Daniel of having this when he helps the old man he accosted and stole from on the road early in the novel and then again when Daniel tries to warn Rosh that he is hurting rather than helping the Jews with his constant raids on their fields. Rosh tells Daniel,"There's a flaw in you, boy, a soft streak....Like a bad streak in a piece of metal....When the day comes there'll be no place for weakness" (110). Rosh defines "weakness" as caring for other people, which is what Jesus defines as "strength." This is one important difference that distinguishes the two leaders and by means of which Daniel must decide his own moral compass.
The easiest way to answer this question is to say that Rosh requires all his people follow his rule and do what he commands, no questions asked. Rosh is an arrogant and callous ruler, full of hate. He wants what he wants, and he cares little how it happens. The things his gang members are expected to do include to live in isolation with the band, to steal, to fight, and to commit themselves to the removal of the Romans from Israel.