should i use redirect or view if validation error exists?

[eluser]Unknown[/eluser]
i have function called register() where it load the view of my registration form,
and the form action is to go to add() function,

inside add() function there's an input validation.
and if there a validation error or message
i redirect it to my register function,

the question is, should i redirect it to register function
or should i use the load->view() to show the form together
with the error message?

i am so confuse ,
please help,
thanks