en_tn_condensed/tit/01/11.md

It is necessary to stop them

"They must be prevented from spreading their teachings" or "They must be stopped from influencing others by their words"

what they should not teach

These are things that are not proper to teach regarding Christ and the Law because they are not true.

for disgraceful profit

This refers to profit that people make by doing things that are not honorable.

are upsetting whole families

"are ruining whole families." The issue was that they were upsetting families by destroying their faith. This may have caused the members of the families to argue with one another.