en_tn_condensed/heb/13/03.md

as if you were bound with them

"as if you were tied up along with them" or "as if you were in prison with them"

who are mistreated

"whom others are mistreating" or "who are suffering"

since you yourselves also are in the body

Possible meanings are 1) because you are human and can suffer likewise, or 2) as if you too were being mistreated.