1
general::
Phrase(s): stand up for someone or something
to take the side of someone or something; to defend someone or something. • I hope you will stand up for me if the going gets rough. • We will have to stand up for our rights someday.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, stick up for. Side with, defend, as in Paul always stands up for what he thinks is right, or Ginny has learned to stick up for her family. The first recorded use of the first term is by Shakespeare in King Lear (1:2), when Edmund, Gloucester's bastard son, says: "Now gods, stand up for bastards!" The colloquial variant was first recorded in 1837.
American Heritage Idioms